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A rather tight grouping of galaxies. Looks like some interaction or merging is about to occur.
A widefield color view is available here:
legacysurvey.org/viewer?ra=13.4515&dec=-13.8561&l...
Establishing HST's Low Redshift Archive of Interacting Systems
All Channels: ACS/WFC F606W
North is 32.05° counter-clockwise from up.
"Redshift" Self Portrait September 2019
A profound meaning and explanation to this picture can be read below. It is an excerpt I found very relevant from The Astrophysical Journal, Published 18 March 2003, A Significant Population of Red, Near-Infrared-selected High-Redshift Galaxies
"In the nearby universe, the reddest galaxies are generally the most massive, with the highest ages, metallicity, and correlation length. It is possible that such a relation already existed in the early universe. The red galaxies found here would be the descendants of galaxies that started to form stars very early, and they would be related to more massive halos than those of the young Lyman break galaxies at z = 3. In this case, their spatial densities are expected to be higher and their correlation length to be enhanced..."
(source: The Astrophysical Journal, April 20, 2003 iopscience.iop.org/article/10.1086/375155 Discussion )
© 2019 Sabine Fischer
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A dwarf galaxy bustling with star formation, as evidenced by the tendrils of emission nebula appearing green here due to the choice of filters. The emission must be very strong indeed, for it is visible even in wideband color. A narrowband filter would bring out a lot of details in the nebula.
In my own mind I call these star seams due to their linear appearance and the way the nebula tends to look like it is flowing out from the vein of star formation. You can see a spectacular example of one of these with appropriate narrowband filters included here: flic.kr/p/pTDvDs
Color comes from this SDSS field:
dr12.sdss.org/fields/name?name=arp+163
HST Proposal:
Establishing HST's Low Redshift Archive of Interacting Systems
Luminosity: ACS/WFC F606W
Red: SDSS i
Green: SDSS r
Blue: SDSS g
North is 20.91° clockwise from up.
Cruising an active galaxy with many star-forming regions in the Abell 2029 galaxy supercluster, the Hullbull RST captures an image of new massive hot blue stars forming in a still expanding supernova remnant of what must have been an extremely massive star, or possibly an area of past chain-reaction supernovae. This image combines spectral data from the infrared sensors (red), and light gathered through the variable density filter delivered by the starChaser. Colored in one of the many Hullbull palettes, the orange/yellow areas of the nebula represent sulfur, green represents ionized oxygen, and blue represents hydrogen.
Not a real space image. Light art.
Composite of two unaltered images. One image using Waterworld technique/100mm lens to create nebula patterns (source light is dry grass, green shrubs, yellow building wall with large orange and red border in bright daylight, and a hand-held black matte background). Second long exposure designed and implmented based on Waterworld image geometry, 100mm lens (base layer/EXIF data) to create stars; two partially masked "burns" to create segregated star color patterns using water droplet technique and red, white, yellow colored LEDs; cover/recompose, create larger stars using blue LEDs. Didn't quite get many of the perimeter blue stars where I wanted them. Close, but no Cee-garrr. Damn.
Plaza de España, Seville
Eximus Wide and Slim (Vivitar Ultra Wide and Slim clone) + Fuji Sensia 100 + xpro
Things have been rough for this galaxy. There are stellar streams strewn all about, the dust disk is warped all over the place, and there's hardly any star formation going on. That's what makes it so cool, though. I love the way the dust disk is pushed and pulled around, but still maintains semblance to a disk.
BONUS: If you look down at the bottom, next to the two red stars, there's the cutest little hourglass nebula I've ever seen. I think it's a planetary nebula, anyway. It's either a planetary nebula that's fairly typical, or the weirdest galaxy I've ever seen. I'll defer to Occam's razor for this one.
Edit: Some Galaxy Zoo people and Phil Plait are shooting holes in my idea that it's anything but a galaxy. Apparently there ARE galaxies that look exactly like this, such as NGC 2665. I'm just gonna redact that whole paragraph for now.
Color from SDSS again. Data for that may be found here:
dr12.sdss.org/fields/name?name=arp156
NASA/ESA/SDSS/Judy Schmidt
Establishing HST's Low Redshift Archive of Interacting Systems
Luminosity: ACS/WFC F606W
Red: SDSS i
Green: SDSS r
Blue: SDSS g
North is 37.73° clockwise from up.
A look at the tidal interaction between NGC 2993 (left) and NGC 2992 (right). It's hard to make out, but I can just barely see slender streams and clumps in the fuzzy, faint bridge between the galaxies. The whole visible system extends quite a bit outside of the frame, and an interesting clump near NGC 2992 can be seen in this photo from Adam Block: www.caelumobservatory.com/gallery/n2992.shtml
I would expect the brighter galaxy to be more massive, but it appears to be falling into the dimmer one. Then again, I could easily be misreading it, and gravity is not necessarily intuitive at a galactic scale.
On top of the usual processing involving getting rid of cosmic rays, I also tried to alleviate some of the distracting bias stripes that were making the bridge details harder to see by simply lightening and darkening the appropriate parts by hand.
Color comes from PanSTARRS this time.
Establishing HST's Low Redshift Archive of Interacting Systems
Luminosity: ACS/WFC F606W
Red: PanSTARRS z
Green: PanSTARRS i
Blue: PanSTARRS g
North is 20.29° clockwise from up.
In a survey of 100,000 galaxies (called Cosmic Evolution Early Release Science, or CEERS), Webb spotted the most distant active supermassive black hole to date, plus two more small early black holes and 11 early galaxies. All of these objects existed in the first 1.1 billion years after the big bang.
Read more: www.nasa.gov/feature/goddard/2023/webb-detects-most-dista...
This image: Researchers using data and images from the James Webb Space Telescope’s Cosmic Evolution Early Release Science (CEERS) Survey identified two supermassive black holes that are more similar in size to Sagittarius A*, the supermassive black hole at the center of our Milky Way galaxy’s center, than other extremely distant galaxies observed earlier by other telescopes. Webb’s spectra show that these black holes weigh only 10 million times the mass of the Sun. Other very distant supermassive black holes we’ve long known about are 1 billion times the mass of the Sun.
Credits: Illustration: NASA, ESA, CSA, Leah Hustak (STScI). Science: Steven Finkelstein (University of Texas at Austin), Dale Kocevski (Colby College), Pablo Arrabal Haro (NOIRLab).
Image description: A graphic titled “Cosmic Evolution Early Release Science (CEERS) Survey, Two Extremely Distant Active Supermassive Black Holes.” The graphic shows the redshift of two active supermassive black holes. At top right is the complete NIRCam image of the field. To its left is a large, continuous pull out, labeled NIRCam imaging, which shows the locations of two objects, with open white boxes. The image is filled with galaxies of different colors, shapes, and sizes. Two white lines from the image connect to pull outs that run to the left of two graphs at the bottom. In the inset images are blurry red dots. The top one reads CEERS 2782, 12.7 billion years. The bottom image reads CEERS 746, 12.8 billion years. To the right are two line graphs corresponding to the two highlighted black holes. These are labeled NIRSpec Microshutter Array Spectroscopy. They show the shift in the position of emission lines.
A magnificent barred spiral galaxy with arms tightly wound into near continuous circles. This was colorized using PanSTARRS z/i/g survey data. I processed the center somewhat heavily to make the lines of dust more apparent.
Establishing HST's Low Redshift Archive of Interacting Systems
Luminosity: ACS/WFC F606W
Red: PanSTARRS z
Green: PanSTARRS i
Blue: PanSTARRS g
North is 45.34° counter-clockwise from up.
NASA Release date: Jan 26, 2011
How far does Hubble see?
This diagram shows how Hubble has revolutionised the study of the distant, early Universe. Before Hubble was launched, ground-based telescopes were able to observe up to a redshift of around 1, about half way back through cosmic history. Hubble’s latest instrument, Wide Field Camera 3 has identified a candidate galaxy at a redshift of 10 — around 96 per cent of the way back to the Big Bang. The forthcoming NASA/ESA/CSA James Webb Space Telescope will see further still.
Credit: NASA, ESA
To read more go to: www.nasa.gov/mission_pages/hubble/science/farthest-galaxy...
NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission.
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A spiral galaxy that recently went through some interactive process, resulting in some stars strewn hither and thither. This viewpoint allows us to see that sections of the disk have been inclined away from the original plane of the galaxy. Dust fades into the background as soon as it loses its stellar backlight.
A nice, color, widefield view of this galaxy is available at the Legacy Survey viewer: legacysurvey.org/viewer?ra=317.3111&dec=-63.2898&...
Establishing HST's Low Redshift Archive of Interacting Systems
All Channels: ACS/WFC F606W
North is 53.04° clockwise from up.
the Multimedia Artist Danny "MushroomBrain" Hennesy
these are some of my eyes, I often use them when I make visional artistery but not always and not all at the same time!
Peace and Noise!
/ MushroomBrain the seer :::)
This NASA/ESA Hubble Space Telescope image features the galaxy LRG-3-817, also known as SDSS J090122.37+181432.3. The galaxy, its image distorted by the effects of gravitational lensing, appears as a long arc to the left of the central galaxy cluster.
Gravitational lensing occurs when a large distribution of matter, such as a galaxy cluster, sits between Earth and a distant light source. As space is warped by massive objects, the light from the distant object bends as it travels to us and we see a distorted image of it. This effect was first predicted by Einstein’s general theory of relativity.
Strong gravitational lenses provide an opportunity for studying properties of distant galaxies, since Hubble can resolve details within the multiple arcs that are one of the main results of gravitational lensing. An important consequence of lensing distortion is magnification, allowing us to observe objects that would otherwise be too far away and too faint to be seen. Hubble makes use of this magnification effect to study objects beyond those normally detectable with the sensitivity of its 2.4-meter-diameter primary mirror, showing us the most distant galaxies humanity has ever encountered.
This lensed galaxy was found as part of the Sloan Bright Arcs Survey, which discovered some of the brightest gravitationally lensed high-redshift galaxies in the night sky.
Text credit: European Space Agency
Image credit: ESA/Hubble & NASA, S. Allam et al.
For more information: www.nasa.gov/image-feature/goddard/2020/hubble-spies-gala...
One of Webb’s most complex instrument modes is with the MIRI Medium Resolution Spectrometer (MRS). The MRS is an integral-field spectrograph, which provides spectral and spatial information simultaneously for the entire field of view. The spectrograph provides three-dimensional ‘data cubes’ in which every pixel in an image contains a unique spectrum. Such spectrographs are extremely powerful tools to study the composition and kinematics of astronomical objects, as they combine the benefits of both traditional imaging and spectroscopy.
“The MRS is designed to have a spectral resolving power (observed wavelength divided by the smallest detectable wavelength difference) of about 3,000. That is high enough to resolve key atomic and molecular features in a variety of environments. At the highest redshifts, the MRS will be able to study hydrogen emission from the first galaxies. At lower redshifts, it will probe molecular hydrocarbon features in dusty nearby galaxies and detect the bright spectral fingerprints of elements such as oxygen, argon, and neon that can tell us about the properties of ionized gas in the interstellar medium. Closer to home, the MRS will produce maps of spectral features due to water ice and simple organic molecules in giant planets in our own solar system and in planet-forming disks around other stars.
“In order to cover the wide 5 to 28 micron wavelength range as efficiently as possible, the MRS integral field units are broken up into twelve individual wavelength bands, each of which must be calibrated individually. Over the past few weeks, the MIRI team (a large international group of astronomers from the USA and Europe) has been focusing primarily on calibrating the imaging components of the MRS. They want to ensure that all twelve bands are spatially well aligned with each other and with the MIRI Imager, so that it can be used to place targets accurately into the smaller MRS field of view. We show some early test results from this alignment process, illustrating the image quality achieved in each of the twelve bands using observations of the bright K giant star HD 37122 (located in the southern sky near the Large Magellanic Cloud).
“Once the spatial alignment and image quality of the several bands are well characterized, the MIRI team will prioritize calibrating the spectroscopic response of the instrument. This step will include determining the wavelength solution and spectral resolution throughout each of the twelve fields of view using observations of compact emission-line objects and diffuse planetary nebulae ejected by dying stars. We show the exceptional spectral resolving power of the MRS with a small segment of a spectrum obtained from recent engineering observations of the active galactic nucleus at the core of Seyfert galaxy NGC 6552. Once these basic instrument characteristics are established, it will be possible to calibrate MRS so that it is ready to support the wealth of Cycle 1 science programs due to start in a few short weeks.”
Read more: blogs.nasa.gov/webb/2022/06/16/webbs-mid-infrared-spectro...
This image: This portion of the MIRI MRS wavelength range shows engineering calibration data obtained of the Seyfert galaxy NGC 6552 (red line) in the constellation Draco. The strong emission feature is due to molecular hydrogen, with an additional weaker feature nearby. The blue line shows a lower spectral resolution Spitzer IRS spectrum of a similar galaxy for comparison. The Webb test observations were obtained to establish the wavelength calibration of the spectrograph. Credit: NASA, ESA, and the MIRI Consortium.
A mostly dark frame with some faint fuzzy dots, flanked by a copy of the same with some incomprehensible labels? This is far from beeing the most beautiful image I ever published, but it easily qualifies as the most interesting! However, it certainly needs quite some explanation:
The image shows a section of sky (roughly 8.5° x 6.5°) in the border area of the constellations Leo, Virgo and Coma Berenices that is home to the northern part of the famous Virgo Galaxy Cluster. This cluster harbors roughly 1300 galaxies and forms the heart of the larger Virgo Supercluster, of which our Milky Way is an outlying member.
Just right of and below the center of the image is Markarian's Chain, a stretch of galaxies that is called a chain because, when viewed from Earth, the galaxies lie along a smoothly curved line. It is named after the Armenian astrophysicist, B. E. Markarian, who discovered their common motion in the early 1960s.
Markarian's Chain was my primary target for this image. As I was running late that evening, I decided not to set up my telescope, but to shoot with my 200mm lens from a tripod equipped with a simple iOptron SkyTracker. Not the most impressive setup and, considering that I was imaging from my light polluted backyard (#5 on the Bortle scale) with a too short focal length, I was not expecting much of a result.
After setting up, I just let the camera shoot away and went for my well-deserved nights rest. The next day, after sorting out the frames with clouds, aircraft or satellite trails, I ended up with 290 shots of 30s each, summing up to 2h25min of usable data. After stacking and processing these frames, I got the above image.
First, I was happy that my primary target was visible at all, but then I started to notice many small galaxies in the image. I therefore started to scrutinize the image systematically. You can see the result in the copy on the right side, where I was able to identify more than 150 galaxies (yellow labels).
Now I was truly impressed. I remembered the Hubble Deep Filed (HDF), showing thousands of galaxies in the early universe and started to think of my image as my personal deep field (PDF)…LOL
The imaged galaxies are roughly 50-60 million lightyears away from earth. While this is a huge distance (it means the light my camera caught was emitted just after the dinosaurs were extinct), it still is a rather small distance on the cosmological scale of the Hubble Deep field.
I started wondering if there are more distant objects in my image. After a dedicated search, I really found some exotic and much more distant objects (red labels). The most distant of them is a quasar named Q1227+120. It has a measured redshift of z=2.458. You can translate this into a cosmological distance of mindboggling 19.2 billion lightyears! The light of this quasar was emitted 11.1 billion years ago. That’s 4/5th of the time that has elapsed since the big bang!
Of course, you can find many images of similar objects taken with giant, professional telescopes. But when I realized that I had imaged an object that almost lies “at the edge of the universe” from a tripod in my backyard, with a simple DSLR camera and a 200mm lens, I was absolutely flabbergasted!
A word of caution:
Even in giant telescopes, these quasars (Quasi Stellar Objects) are just tiny, star-like dots of light. In my image, they are at the very limit of discernibility and you will have to download and open the image in full resolution to see them. But they are there – trust me!
Acknowledgement:
My star charts and planetarium programs were unable to go deep enough for the data of the image.
For my "research" I had to get access to professional quality data and found these in the "Aladin sky atlas" developed at CDS, Strasbourg Observatory, France → 2000A&AS..143...33B and 2014ASPC..485..277B.
Aladin is a free interactive sky atlas, allowing the user to visualize digitized astronomical images or full surveys, superimpose entries from astronomical catalogues or databases, and interactively access related data and information from the Simbad database, the VizieR service and other archives for all known astronomical objects in the field. It was developed for professional astronomers, but it is also a great toy for the interested amateur.
ARP 294, Interacting Galaxies with Stellar Streams, NGC 3786 and NGC 3788, Ursa Major
NGC3786 and NGC3788 are a tight pair of apparently interacting spiral galaxies in the constellation of Ursa Major, first documented by W. Herschel around 1790. They are listed as ARP 294 in the Atlas of Peculiar Galaxies which includes examples of unusual structures found among galaxies. As the chart below indicates, the galaxies are very similar in angular size, around 2.2 arcmin, apparent magnitude of 13.3 (g), and morphological classification as peculiar intermediate spirals with a ring. Their redshift-based distances are 125.4 and 123.8 million light years respectively, suggesting a separation between them of 1.6 Mly. However, redshift-based distance estimates assume that redshift recession is due exclusively to the expansion of space, and do not correct for galaxies' "peculiar velocities" through space. For redshifts less than 0.01, or distances less than 138 Mly, it is generally accepted that redshift-independent distance measurements, such as the Cepheid period-luminosity relation, are more accurate. According to the NED extragalactic database, median redshift-independent distances for the pair are 158 and 183 Mly respectively, indicating a separation between them of 25 Mly. In either case, as their relatively undisturbed spiral arms confirm, the galaxies appear close due to similar lines of sight, and have not yet undergone major deformations due to close physical contact.
However, both galaxies are still interacting, although not with each other. Each one displays a faint stellar stream of a dwarf falaxy which appears to be in the process of merging. And, each displays a bright blue sector in its galactic disk where its intersecting stellar stream causes a blaze of starburst activity. On the annotated image the streams are marked as A and B, while the starburst regions are marked as S1, S2, and S3. Stream A appears to follow a straight line resulting from gravitational dispersal of a dwarf galaxy as it directly approached NGC3788, causing an explosion of starburst activity (S1) as it traversed the N perimeter of the spiral disk. Meanwhile, Stream B appears as a faint oval loop formed by stellar debris from a disrupted dwarf galaxy which has merged with NGC3786, and made at least one full orbit around it. Along the S and E perimeter of the main galaxy, two luminous blue regions (S2 and S3) indicate starburst activity at the intersections between the looping stellar stream and the main galactic disk.
Physical properties of the galaxies are listed in the chart on the annotated image. Values enclosed in parentheses are based on median redshift-independent distance measurements obtained from the NED database. Depending on the distance method used, the galaxies are between 25 and 50% smaller than the Milky Way, 30 to 70% less bright, and of approximately equal size to each other. Although both galaxies have faint emission lines in the spectrum of their nuclei, and the nucleus of NGC3786 appears bright in the X-ray band, NED extragalactic database does not register an active galactic nucleus in either galaxy.
Since galactic interactions and mergers significantly influence stellar dynamics, the rates of consumption, production, and the distribution of gas and dust, synthesis of new elements (metallicity), and the nature of the galactic nucleus, galactic encounters are of great interest in the study of galactic evolution.
The attached image includes a number of remote background galaxies and two quasars listed in the chart below. The most remote of these is LAMOST J114003.83+315503.5, lying at a light travel (lookback time) distance of 8.85 Bly. The object labeled G1 is identified by Simbad as a galaxy LAMOST J113941.45+315442.2, no angular size specified, which is not listed in the NED database. The object appears starlike on high resolution HST photographs, and is most likely mis-categorized.
HST image
Image details:
-Remote Takahashi TOA 150 x 1105mm, SBIG STF-8300C, Paramount GT GEM
-OSC 36 x 300 sec, 2x drizzle, 40% linear crop
-Software: DSS, XnView, StarNet++ v2, StarTools v1.3 and 1.8, Cosmological Calculator v3
October 2017
The sky glows red as flame amid battering waves and pattering rain along Lake Superior in autumn.
Copyright © 2017 Richard Thompson.
A soft, fluffy, irregular dwarf galaxy with a few areas of star formation. Could be a nice place to live.
NASA/ESA/SDSS/Judy Schmidt
Color comes from this SDSS field:
dr12.sdss.org/fields/name?name=arp+264
HST Proposal:
Establishing HST's Low Redshift Archive of Interacting Systems
Luminosity: ACS/WFC F606W
Red: SDSS i
Green: SDSS r
Blue: SDSS g
North is 59.29° counter-clockwise from up.
One of the 22 Mercedes Benz CLK GTR is currently exposed at Audrain Musuem in Newport, RI.
This great expo is showing a lot a very nice supercars !!
This one is owned by Gioel Molinari known for having some other nice cars (green F40 or F50) and was sold last year by DK Engineering in UK after having set the famous holly trinity photoshoot for Octane.
While pleasing to the eye, this galaxy seems less peculiar than some of the other galaxies in Arp's catalog. Given that he was looking for ejections from the centers of galaxies, I am guessing he was interested in the very bright piece of arm that seems somewhat broken off from the rest of the galaxy. Looks like a lot of star formation, there.
A color widefield view is available at the Legacy Survey viewer: legacysurvey.org/viewer?ra=15.1909&dec=-9.1851&la...
Establishing HST's Low Redshift Archive of Interacting Systems
All Channels: ACS/WFC F606W
North is 0.97° counter-clockwise from up.
A beautiful collision is underway.
A good color view is available from the DECaLS viewer: legacysurvey.org/viewer?ra=148.2908&dec=7.8657&zo...
Data from the following proposal is used to create this image:
Establishing HST's Low Redshift Archive of Interacting Systems
All channels: ACS/WFC F606W
North is 23.75° counter-clockwise from up.
I think there are at least two galaxies here in the midst of a very confusing merger. I mean, all mergers and many galaxies are confusing to some extent, but this one really confuses me. I've marked what I think are two galactic nuclei. On the other hand, it looks a bit like a snake turning its head and opening its mouth, which is cool.
There is a faint line going diagonally across the left half of the image. This is possibly some space junk or some other small object that is close to Earth. I normally remove these, but this one is less obtrusive, making it a good example without detracting too much from the image. Sometimes these are much brighter, and are a big hassle to deal with.
A widefield version is available from the Legacy Survey viewer: legacysurvey.org/viewer?ra=21.3389&dec=34.0239&la...
Establishing HST's Low Redshift Archive of Interacting Systems
All Channels: ACS/WFC F606W
North is 23.44° clockwise from up.
Abell 39 Hercules, Planetary Nebula
This low surface brightness planetary nebula in Hercules was discovered around 1955 by Abell and Wilson during the National Geographic Society Palomar Observatory Sky Survey. Planetary nebulae are formed when red giant stars run out of nuclear fuel in their cores, gravitationally collapse into white dwarfs, and eject their outer layers into an expanding shell of gas. Illuminated by the central white dwarf, the shell remains visible in blue-green light for tens of thousands of years before diffusing into space.
Abell 39 is about 3 arcmin in angular diameter, 13.7 in apparent magnitude, and 2.5 LY in radius, lying at the distance of 6,800 LY. The central star is a 15.5 magnitude subdwarf of spectral class O, indicating surface temperature between 40,000 and 100,000 K, about ten times hotter than the Sun. The nebula is almost perfectly spherical because it is undeformed by movement through the interstellar medium. The E rim is obviously denser than the W, and the central star is slightly displaced toward the W probably because the gas ejection was asymmetrical. Based on the expansion speed of around 35 km/sec, the nebula is approximately 22,000 years old.
As the annotated image shows, the field is strewn with small, faint galaxies. The most remote one is PGC 1821778 with a redshift of 0.13163, which indicates the lookback time distance of 1.67 billion LY, and apparent recession speed of 36,900 km/sec. Professional images show that the two "knots" in the nebula marked as GAL are actually faraway background galaxies whose light is passing through the gaseous shell.
The attached image was taken from my (mostly) dark site with a TSapo100q astrograph, Sigma APO 1.4x tele-extender (100 x 812 mm), full spectrum modified Canon T3i camera, Astronomik L3 filter, iEQ30 pro mount, and Orion 60mm f4 SSAGpro autoguider. The image is a stack of 25 x 300 second exposures, ISO 1600, 25% crop, processed with 30 dark and 30 bias frames. Limiting magnitude on the original is 19. Software used was PHD2, DSS, XnView, and StarTools.
Still cruising in the vicinity of Abell 2029, the Hullbull RST nabs an image of part of a nearby nebula that exhibits somewhat similar geometry to the Pillars of Creation. Colored in one of the many Hullbull palettes, the red/yellow areas of the nebula represent sulfur, green represents ionized oxygen, and blue represents hydrogen. Areas of dusty dark nebula can be seen in the nebula formation. Background stars and stars within the nebula are either obscured or exhibit significant red shift.
Not a real space image. Light art.
Composite of two unaltered images. One image using Waterworld technique/100mm lens to create nebula patterns (source light is dry grass, green shrubs, yellow building wall with large red letters in bright daylight, and a hand-held black matte background). Second long exposure, 100mm lens (base layer/EXIF data) to create stars; several partially masked "burns" to create segregated star color patterns using water droplet technique and red, white, blue, yellow colored LEDs; cover/recompose, create larger stars using white and blue LEDs, with and without diffraction filter. (Am thinking the white stars might have looked better without the diffraction filter...?)
Interesting galaxy with some vague spiral rotational patterns to it, and a bright node at the end of an arm. Looks a bit like a smaller dwarf merging with a larger dwarf irregular galaxy.
A widefield color view is available at the Legacy Survey viewer: legacysurvey.org/viewer?ra=163.6506&dec=56.9876&l...
Establishing HST's Low Redshift Archive of Interacting Systems
All Channels: ACS/WFC F606W
North is 16.86° clockwise from up.
UGC 4277 Distant Galaxy Group, Lynx
UGC4277 is a giant edge-on spiral galaxy, morphological type SC, which is gravitationally bound to, but not tidally interacting with, two smaller galaxies, MCG+09-14-017 and MCG+09-14-012. Since they have similar redshifts and distances, their relative sizes and separation on the image are essentially to scale. From the measurable properties (redshift, apparent magnitude, and angular size), we can derive UGC4277 light travel distance (lookback time) of 250 Mly, redshift recession velocity of 5,407 km/s, and actual diameter of 284,000 ly. This is about 30% larger than the Andromeda Galaxy, and nearly twice the size of the Milky Way. Due to its edge-on orientation, its integrated apparent magnitude and the calculated absolute magnitude are significantly underestimated for two reasons. First, it presents to the observer a much smaller surface area than a face-on galaxy. And second, much of its starlight is absorbed and scattered by thick layers of gas and dust in its galactic plane. Prominent dark dust lanes are easily visible even at the low resolution and small scale of the attached image. UGC4277 has an active galactic nucleus (AGN), which indicates the presence of an accreting central supermassive black hole (SMBH.
Edge-on galaxies are of great interest in the study of galactic evolution because the dynamic distribution of stars, dust, and atomic gas can be analyzed both along the galactic plane and perpendicularly to it. Radio frequency studies of UGC4277 by Allaert et al. (2015) revealed the presence of a primordial atomic hydrogen envelope, three times thicker than the visible disk. As this gas gravitates toward the galactic plane, it condenses into clouds of molecular gas, which eventually collapse to form a "rain" of low metallicity stars. Metals (in astronomy all elements heavier that helium) are produced by stellar nucleosynthesis, and are dispersed into the interstellar medium (ISM) by stellar winds, supernova explosions, and neutron star collisions. Through various processes, a fraction of metals condenses into small dust grains which on average constitute about 0.1% of the galactic baryonic mass. While most of the dust resides in the galactic plane, a part of it can be detected in the form of a "dust-scattered ultraviolet halo" around the galaxy. This "extraplanar" dust appears to be defying gravity, probably suspended by radiation pressure and the plumes of hot gases arising from the galactic disk and bulge. Assuming similar total dust mass fraction, it is expected that starburst galaxies with numerous hot, blue stars and more intense ultraviolet radiation would manifest more prominent extraplanar dust halos. Jong-Ho Shinn (2018), who compared visible band to GALEX ultraviolet images of 23 edge-on galaxies reported, among other findings, a moderate to low extraplanar dust halo around UGC4277, implying a similarly moderate to low star formation rate.
The other two galaxies in the group are MCG+09-14-017 and MCG+09-14-012. The former is oriented face-on, and has a LINER type active galactic nucleus. It is approximately half the diameter and half the brightness of the Milky Way. Both appear to be barred spirals with slightly deformed spiral arms probably due to mild tidal interaction in the remote past. A number of small, background galaxies, listed in the chart on the annotated image, lie at distances between 540 and 1,610 million light years. Four bright quasars are also identified. The most remote of these is SDSS J081428.78+524045.2, located at a light travel distance (lookback time) of 10.4 billion light years. In the present cosmological epoch, its proper (comoving) distance is 17 Bly, and proper recesion velocity 367,941 km/s. Since its recession velocity is presently superluminal, the quasar lies beyond the cosmic event horizon, and the light it is presently emitting can never reach us.
Image details:
-Remote Takahashi TOA 150 x 1105 mm, Paramount GT GEM
-OSC 35 x 300 sec, 2x drizzle, 50% linear crop
-Software: DSS, XnView, Starnet++ v2, StarTools v1.3 and 1.7, Cosmological Calculator v3
When the universe was about 3 billion years old, just 20% of its current age, it experienced the most prolific period of star birth in its history. But when NASA's Hubble Space Telescope and the Atacama Large Millimeter/submillimeter Array (ALMA) in northern Chile gazed toward cosmic objects in this period, they found something odd: six early, massive, "dead" galaxies that had run out of the cold hydrogen gas needed to make stars.
Without more fuel for star formation, these galaxies were literally running on empty. The findings are published in the journal Nature.
"At this point in our universe, all galaxies should be forming lots of stars. It's the peak epoch of star formation," explained lead author Kate Whitaker, assistant professor of astronomy at the University of Massachusetts, Amherst. Whitaker is also associate faculty at the Cosmic Dawn Center in Copenhagen, Denmark. "So what happened to all the cold gas in these galaxies so early on?"
This study is a classic example of the harmony between Hubble and ALMA observations. Hubble pinpointed where in the galaxies the stars exist, showing where they formed in the past. By detecting the cold dust that serves as a proxy for the cold hydrogen gas, ALMA showed astronomers where stars could form in the future if enough fuel were present.
Using Nature's Own Telescopes
The study of these early, distant, dead galaxies was part of the appropriately named REQUIEM program, which stands for Resolving QUIEscent Magnified Galaxies At High Redshift. (Redshift happens when light is stretched by the expansion of space and appears shifted toward the red part of the spectrum. The farther away a galaxy is with respect to the observer, the redder it appears.)
The REQUIEM team uses extremely massive foreground galaxy clusters as natural telescopes. The immense gravity of a galaxy cluster warps space, bending and magnifying light from background objects. When an early, massive, and very distant galaxy is positioned behind such a cluster, it appears greatly stretched and magnified, allowing astronomers to study details that would otherwise be impossible to see. This is called "strong gravitational lensing."
Only by combining the exquisite resolution of Hubble and ALMA with this strong lensing was the REQUIEM team able to able to understand the formation of these six galaxies, which appear as they did only a few billion years after the big bang.
"By using strong gravitational lensing as a natural telescope, we can find the distant, most massive, and first galaxies to shut down their star formation," said Whitaker. "I like to think about it like doing science of the 2030s or 40s – with powerful next-generation space telescopes – but today instead by combining the capabilities of Hubble and ALMA, which are boosted by strong lensing."
"REQUIEM pulled together the largest sample to date of these rare, strong-lensed, dead galaxies in the early universe, and strong lensing is the key here," said Mohammad Akhshik, principal investigator of the Hubble observing program. "It amplifies the light across all wavelengths so that it's easier to detect, and you also get higher spatial resolution when you have these galaxies stretched across the sky. You can essentially see inside of them at much finer physical scales to figure out what's happening."
Live Fast, Die Young
These sorts of dead galaxies don't appear to rejuvenate, even through later minor mergers and accretions of nearby, small galaxies and gas. Gobbling up things around them mostly just "puffs up" the galaxies. If star formation does turn back on, Whitaker described it as "a kind of a frosting." About 11 billion years later in the present-day universe, these formerly compact galaxies are thought to have evolved to be larger but are still dead in terms of any new star formation.
These six galaxies lived fast and furious lives, creating their stars in a remarkably short time. Why they shut down star formation so early is still a puzzle.
Whitaker proposes several possible explanations: "Did a supermassive black hole in the galaxy's center turn on and heat up all the gas? If so, the gas could still be there, but now it's hot. Or it could have been expelled and now it's being prevented from accreting back onto the galaxy. Or did the galaxy just use it all up, and the supply is cut off? These are some of the open questions that we'll continue to explore with new observations down the road."
The Hubble Space Telescope is a project of international cooperation between NASA and ESA (European Space Agency). NASA's Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, in Washington, D.C.
For more information: www.nasa.gov/feature/goddard/2021/hubble-finds-early-mass...
Trying to get caught up on some galaxies from Prop15446 again. Here is a pair of interacting galaxies. Visible at the bottom left edge is a third member. Another galaxy that may have had an encounter with this group is not visible within the image.
You can see a beautiful widefield color view from the Legacy Survey viewer:
legacysurvey.org/viewer?ra=344.5309&dec=-3.7903&l...
Establishing HST's Low Redshift Archive of Interacting Systems
All Channels: ACS/WFC F606W
North is 1.40° clockwise from up.
Here is a nice interaction with one galaxy very clearly in front of the other, allowing for us to make out the silhouettes of dust that we may not otherwise be able to see.
Data from the following proposal is used to create this image:
Establishing HST's Low Redshift Archive of Interacting Systems
All channels: ACS/WFC F606W
North is 35.30° clockwise from up.
[Version Française en haut / English version below]
Lien photo d'origine : flic.kr/p/2p21GPo
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Note sur la V2 : Un grand merci à Damien Guillard, un ptit gars qu'est pas mauvais en astro, à m'avoir aidé à tirer le meilleur du signal de cette photo.
La différence est un traitement BlurXTerminator sur ma photo, fait par Damien. J'ai utilisé sa sortie affinée comme calque parmi les calques existants pour faire ressortir les nébuleuses.
Note about the V2 : A special thank to Damien Guillard,a young fella who's pretty good at astrophotography, for helping me get the most out of the signal in this photo.
The difference is a BlurXTerminator treatment on my photo, done by Damien. I used his refined output as a layer among the existing layers to bring out the nebulae.
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[Version française]
La galaxie du Triangle (Messier 33)
Il y a deux ans, j'avais fait une petite session sur la galaxie M33. Je n'en étais qu'à moitié satisfait car triop peu de poses (1h11 seulement). Voilà ce que j'écrivais à l'époque : "j'ai un peu galéré ce soir là parce que je testais ma configuration mobile (loin de la maison), avec une reprise des sessions astro avec le télescope (il fallait se réhabituer depuis le printemps), beaucoup d'humidité et je n'avais pas encore fabriqué mes résistances chauffantes, mon autoguidage ne fonctionnait pas parce que j'avais mal configuré mon wifi ... Du coup la photo n'est pas top car j'ai du jeter la moitié des poses à cause de la buée, et aussi parce que je n'ai toujours pas mis mon correcteur de coma. Elle a un goût de revanche du coup !". Eh bien ça y est ! je l'ai ma revanche. J'ai pas mal attendu ne trouvant jamais le temps ou la météo adaptée pour M33.
Cataloguée par Charles Messier en 1764, elle a du être observée avant. Sous un ciel extraimement clair, il est effectivement possible de distinguer sa tâche laiteuse à l'oeil nu. J'en ai fait l'expérience le 06/09/23 (deuxième session). Avec de bonnes jumelles, si vous savez où elle se trouve, sa détection est un peu plus facile (elle reste très sombre).
Sa distance est comprise entre 2.38 et 3.07 millions d'années lumières (elle n'est pas connue avec précision), et elle fait environ 50000 à 60000 AL de diamètre. La masse de cette galaxie est d'environ 60 milliards de masses solaires, mais seulement 17% de sa masse vient de matière ordinaire ; 83% de sa masse provient de cette composante de l'univers qu'on ne détecte pas encore, mais dont on mesure la présence, et que l'on nomme matière noire (pour signifier qu'on ne la voit pas). Les presque 12h d'exposition en HOO (Hydrogène Alpha dans le rouge + Oxygène III dans le bleu/vert) font ressortir fortement les nébuleuses, ces grandes tâches rouges et bleues qui sont des nuages denses en gaz échauffés par les étoiles environnantes. Dans notre galaxie, vous pouvez facilement observer la grande nébuleuse d'orion ou la nébuleuse de la lagune. Là, on voit leur équivalent à 2-3 millions d'années lumières. Ces nébuleuses sont des régions d'intense formation stellaire. Certaines des structures observables dans M33 ont été répertoriées dans les catalogue NGC et IC notamment, en particulier NGC 588, NGC 592, NGC 595 et NGC 604. Vous pourrez facilement les repérer en vous servant de l'astrométrie faite sur cette photo : nova.astrometry.net/annotated_full/9241132
J'ai également fait une version annotée dans laquelle j'ai repéré par des mires vertes les galaxies que j'ai repérées sur la photo. J'ai aussi fait quelques zooms sur des nébuleuses de M33 que je trouvais particulièrement jolies.
Les galaxies annotées sont :
- PGC 5648 : paire de galaxies ; magnitude 15.8 ; distance non connue ; taille apparente 0.61 min d'arc
- PGC 5575 : magnitude 15.22 ; distance 609 millions AL ; diamètre 126900 AL ; taille apparente 42.8 arcsec ; vitesse radiale d'éloignement 12944 km/s
- PGC 5899 : magnitude 14.91 ; distance estimée par redshift (0.03462) 476.7 millions d'AL / distance Hubble 490.77 millions AL ; diamètre 143200 AL ; taille apparente 59.8 arcsec ; vitesse radiale d'éloignement 10200 km/s
Je ne suis pas parvenu à trouver les références pour toutes les autres. NB: je suis à peu près certain que tous ces objets avec une mire sont des galaxies, d'une part à cause de leur forme la plupart du temps sans ambiguité, sinon parce que j'ai poussé les curseurs des courbes de luminosité pour les contraster du fond et faire ressortir leur nature, mais également parce qu'ils apparaissent de la même manière dans les images du Deep Sky Survey. Certains de ces objets ont des magnitudes comprises entre 17 et 18.
Sinon, pour les amateurs de BDs, Vinéa (fr.wikipedia.org/wiki/Vinéa), la planète aux trois soleils sur laquelle se rend plusieurs fois Yoko Tsuno dans ses aventures, est supposée se trouver dans la galaxie du triangle.
* Matériel :
Télescope Newton Skywatcher 150/750
Correcteur de coma
Monture Skywatcher AZ-EQ5
Capteur Canon 1200 D modifié (défiltré partiellement)
Filtre Optolong L-Enhance (sur 3 sessions).
Autoguidage Asi 120mm + Kepler 50/162 + Raspberry Pi3 + PhD Guiding
* Réglages :
800 iso ; poses de 90 s espacées de 5 sec.
DOFs systématiquement refaits (Darks et Flats ; Offsets conservés) et constitués de Darks>35, Offsets=30, Flats>45
* sessions et temps d'exposition :
22/08/23 : 116 brutes 90s (2h54) + DOFs - L-Enhance (H-Alpha + H-Beta + O III -> HOO)
06/09/23 : 164 brutes 90s (4h06) + DOFs - L-Enhance (H-Alpha + H-Beta + O III -> HOO)
08/09/23 : 197 brutes 90s (4h55) + DOFs - L-Enhance (H-Alpha + H-Beta + O III -> HOO)
09/09/23 : 189 brutes 90s (4h43) + DOFs - pas de filtre (spectre visible -> RVB)
Soit un cumul total de 16h39 (dont 11h55 en Ha+HB+OIII) ce qui constitue de loin mon record en temps d'exposition sur une même cible.
* Qualité du ciel : Excellente : la galaxie du triangle (M33, mag 6.27) était bien visible à l'œil nu 3 nuits sur 4. De même pour M4.
* Lune : entre 50% et 20% , seulement présente en fin de nuit.
* Traitement :
J'ai traité chaque session individuellement produisant une image Ha et une image OIII pour chaque session avec filtre, et une image RVB pour la dernière session.
Toute la phase du prétraitement jusqu'à post-traitement des sessions Ha, OIII et RVB séparées a été faite sous Siril. Le traitement complet est le suivant : 1) prétraitement des brutes par les DOFs, 2) retrait de la trame horizontale pour chaque image, 3) extraction du gradient linéaire pour chaque image, 4) extraction Ha / OIII pour les sessions avec filtre 5) alignement des images, 6) empilement, 7) retrait de la trame sur l'image empilée (il en reste un peu), 8) retrait du gradient (non linéaire), 9) déconvolution (PSF des étoiles), 10) étalonnage des couleurs (d'après catalogue pour l'image RVB) sinon manuel, 11) étirement hyperbolique généralisé, 12) histogramme, 13) suppression du bruit vert.
Les images Ha de chaque session ont été alignées puis cumulées (moyenne avec rejet) pour n'en former qu'une. De même pour les images OIII. De là, une image couleur composite HOO (RVB=Ha-OIII-OIII) a été générée.
L'image HOO et l'image RVB ont été ensuite alignées entre elles sous Siril. Pour chacune de ces images alignées, j'ai généré une starless et un starmask avec Starnet V2.
A partir de là, j'ai fait l'assemblage des quatres images alignées (2 starless et 2 starmasks) sous Gimp (en travaillant avec plusieurs calques duplicant ces images pour faire ressortir tantôt les couleurs, tantôt les contrastes).
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[English version]
The Triangulum galaxy (M33).
Two years ago, I had a small session on the M33 galaxy. I was only half satisfied because there were too few exposures (only 1 hour and 11 minutes). Here's what I wrote back then: 'I struggled a bit that evening because I was testing my mobile setup (far from home), getting back into astrophotography sessions with the telescope (had to reacquaint myself since spring), dealing with high humidity, and my autoguiding wasn't working because I had misconfigured my Wi-Fi... So, the photo isn't great because I had to discard half of the exposures due to dew, and also because I still hadn't put on my coma corrector. It feels like a rematch now!' Well, here it is! I finally got my rematch. I had to wait quite a while, never finding the right time or weather conditions for M33.
Cataloged by Charles Messier in 1764, it must have been observed before. Under an extremely clear sky, it's actually possible to distinguish its milky patch with the naked eye. I experienced this on 06/09/23 (second session). With good binoculars, if you know where to look, its detection is a bit easier (it remains quite dark).
Its distance is estimated to be between 2.38 and 3.07 million light-years (it's not precisely known), and it's about 50,000 to 60,000 light-years in diameter. The mass of this galaxy is about 60 billion solar masses, but only 17% of its mass comes from ordinary matter; 83% of its mass comes from that component of the universe that we can't yet detect but whose presence we measure, and we call it dark matter (to signify that we can't see it). The nearly 12 hours of exposure in HOO (Hydrogen Alpha in red + Oxygen III in blue/green) strongly highlight the nebulae, those large red and blue patches that are dense clouds of gas heated by surrounding stars. In our galaxy, you can easily observe the Orion Nebula or the Lagoon Nebula. Here, we see their equivalent at 2-3 million light-years. These nebulae are regions of intense star formation. Some of the structures observable in M33 have been cataloged in the NGC and IC catalogs, notably NGC 588, NGC 592, NGC 595, and NGC 604. You can easily locate them using the astrometry done on this photo: nova.astrometry.net/annotated_full/9241132 .
I also created an annotated version in which I marked galaxies I identified in the photo with green crosshairs. I also zoomed in on some nebulae in M33 that I found particularly beautiful.
The annotated galaxies are:
- PGC 5648: Pair of galaxies; magnitude 15.8; distance unknown; apparent size 0.61 arcminutes.
- PGC 5575: Magnitude 15.22; distance 609 million light-years; diameter 126,900 light-years; apparent size 42.8 arcseconds; radial velocity of recession 12,944 km/s.
- PGC 5899: Magnitude 14.91; estimated distance through redshift (0.03462) 476.7 million light-years / Hubble distance 490.77 million light-years; diameter 143,200 light-years; apparent size 59.8 arcseconds; radial velocity of recession 10,200 km/s.
I couldn't find references for all the others. Note: I'm fairly certain that all these objects with crosshairs are galaxies, either because of their unambiguous shape or because I adjusted the brightness curves to make them stand out from the background and reveal their nature. Additionally, they appear in a similar manner in Deep Sky Survey images. Some of these objects have magnitudes ranging from 17 to 18.
Otherwise, for comic book fans, Vinéa (en.wikipedia.org/wiki/Vin%C3%A9a), the planet with three suns that Yoko Tsuno visits several times in her adventures, is supposed to be located in the Triangle Galaxy.
* Equipment:
Skywatcher Newton Telescope 150/750
Coma Corrector
Skywatcher AZ-EQ5 Mount
Modified Canon 1200D Sensor (partially defiltered)
Optolong L-Enhance Filter (across 3 sessions)
Autoguiding with Asi 120mm + Kepler 50/162 + Raspberry Pi3 + PhD Guiding
* Settings:
800 ISO; 90-second exposures spaced 5 seconds apart.
Dark, Offset, and Flat frames systematically taken (Darks > 35, Offsets = 30, Flats > 45).
* Sessions and Exposure Times:
08/22/23: 116 raw 90s exposures (2h54) + Dark, Offset, and Flat frames - L-Enhance (H-Alpha + H-Beta + O III -> HOO)
09/06/23: 164 raw 90s exposures (4h06) + Dark, Offset, and Flat frames - L-Enhance (H-Alpha + H-Beta + O III -> HOO)
09/08/23: 197 raw 90s exposures (4h55) + Dark, Offset, and Flat frames - L-Enhance (H-Alpha + H-Beta + O III -> HOO)
09/09/23: 189 raw 90s exposures (4h43) + Dark, Offset, and Flat frames - No filter (visible spectrum -> RGB)
For a total cumulative exposure time of 16h39 (including 11h55 in Ha+HB+OIII), which is by far my longest exposure on a single target.
* Sky Quality: Excellent - The Triangulum Galaxy (M33, mag 6.27) was clearly visible to the naked eye on 3 out of 4 nights. The same applies to M4.
* Moon: Between 50% and 20%, only present in the late night.
* Processing:
I processed each session individually, producing an Ha and an OIII image for each filtered session and an RGB image for the last session. The entire pre-processing to post-processing phase for separate Ha, OIII, and RGB sessions was done in Siril. The complete processing is as follows: 1) Pre-processing of raw frames using Darks, 2) Removal of horizontal banding for each image, 3) Linear gradient removal for each image, 4) Ha / OIII extraction for filtered sessions, 5) Image alignment, 6) Stacking, 7) Further removal of remaining banding in the stacked image, 8) Non-linear gradient removal, 9) Deconvolution (PSF of stars), 10) Color calibration (catalog-based for the RGB image, manual otherwise), 11) Generalized hyperbolic stretch, 12) Histogram, 13) Green noise removal.
The Ha images from each session were aligned and then averaged (mean with rejection) to form one image. Likewise for the OIII images. From there, an HOO color composite image (RGB=Ha-OIII-OIII) was generated.
The HOO image and the RGB image were then aligned with each other in Siril. For each of these aligned images, I created a starless and a starmask using Starnet V2.
From there, I assembled the four aligned images (2 starless and 2 starmasks) in Gimp (working with multiple layers duplicating these images to bring out colors and contrasts as needed).
A handsome lenticular with a chiffon of dust draped against its nucleus with all the grace nature can offer. I initially thought this was a shelled elliptical galaxy, but when I looked at it more intently, I realized there was a soft bar and a tightly wound spiral structure. The alignment of the dust is in apparent opposition to the face-on disk of the galaxy. I am not confident in this explanation and am tempted to interpret it as an elliptical with some spiral shapes embedded within.
Establishing HST's Low Redshift Archive of Interacting Systems
All Channels: ACS/WFC F606W
North is 10.09° clockwise from up.
A picturesque scene of a barred spiral galaxy. This is only half of an interacting pair. The other galaxy is just off the right edge. It is probably a safe assumption to make that not much interaction has occurred yet, as things seem fairly organized into spiral arms at the moment. A good bit of star formation is ongoing, given the various puffs of glowing gas and bright star clusters.
I'm hoping one day the other half of this system will be imaged, but it looks like there aren't any plans for it right now.
Data from the following proposal is used to create this image:
Establishing HST's Low Redshift Archive of Interacting Systems
All channels: ACS/WFC F606W
North is 4.70° clockwise from up.
This image looks especially terrible with whatever Flickr has done to it. Download the png.
Data from the following proposal is used to create this image:
Establishing HST's Low Redshift Archive of Interacting Systems
All channels: ACS/WFC F606W
North is 46.29° clockwise from up.
NGC 4725 Coma Berenices, A One-Armed Spiral Galaxy and 7 Quasars
NGC 4725 is a large intermediate spiral galaxy in the constellation of Coma Berenices, first documented by W. Herschel in 1785. It is the brightest, but relatively isolated, member of the Coma I Galaxy Group, that is itself a part of the Virgo Galaxy Supercluster which includes our own Milky Way.
Its morphological classification is SAB (r)ab pec, indicating a weakly barred, tightly wound spiral galaxy with a complete ring. The galaxy was assigned the "peculiar" descriptor for several reasons. The ring structure is not concentric with the galactic nucleus, and displays elliptical motion. Unlike most spiral galaxies, NGC 4725 displays only a single spiral arm. And, its galactic disk is warped relative to the galactic plane. These anomalies are almost certainly due to strong gravitational interaction with the neighboring NGC 4747 (ARP 159), which is even more highly deformed. Further evidence of interaction, and probable mergers with smaller satellites, comes from the densities in the faint outer parts of the galactic disk suggestive of "stellar streams". These are marked with "S" on the annotated image. Bright blue OB Associations within the ring and along the spiral arm indicate a high star formation rate (SFR), also triggered by tidal interaction. The reddish color along the inner NE edge of the ring is due to Ha fluorescence of hydrogen clouds partially ionized by the ultraviolet radiation emanating from the swarm of very hot and massive young stars. These "stellar nurseries" are especially prominent on infrared images taken by the Spitzer Space Telescope. Spectroscopic studies of the central region indicate the presence of an active galactic nucleus (AGN) of the Seyfert 2 type, caused by a central suppermassive black hole. SIMBAD extragalactic database lists several radio sources without optical counterparts that may be due to compact clouds of neutal hydrogen. It also lists two ultra-luminous X-ray sources (ULX) which are thought to be associated with moderately accreting intermediate-mass black holes (IMBH).
Based on measurable data, NGC 4725 lies at a light travel distance (lookback time) of 41.1 Mly. This is based on the median value of 48 redshift-independent distance estimates which span an unusually wide range of nearly 3. From the distance, angular size, and apparent magnitude we can derive the actual diameter of 114,000 ly and an absolute magnitude of -21.06, approximately 1.25 times brighter than the Milky Way. From the redshift, which is due to the expansion of space and the galaxy's "peculiar velocity" through space, we calculate a recession velocity of 1,209 km/s. (See the note at the bottom of the chart).
The other prominent object in the field is NGC 4712, an emission line barred spiral galaxy with a curiously attenuated central region, possibly obscured by dust and gas. It lies in the faraway background at a distance of 203 Mly, and is about 122,000 ly in diameter - approximately the size of the Milky Way, but only half as bright.
The field is strewn with numerous remote galaxies, most of which have no identifier or observation data listed. A number of these peer through the translucent envelope of NGC 4725, and are marked with letter "G" on the annotated image.
The field also includes seven very distant quasars (QSOs) listed in the attached chart. At this time, some are substantially brighter and some fainter than their photometric data indicate. Letter "X" on the annotated image indicates the locations of two fairly bright quasars which have apparently faded beyond the limiting magnitude of approximately 20.5. The last six quasars on the list have superluminal "proper recession velocities" in the present epoch. They have receded beyond the "cosmic event horizon", and the light they are now emitting can never reach us. The last two on the list are "hyperluminous quasars", more than 2,000 times brighter than the entire Milky Way galaxy. SDSS J125125.57+252026.2 is the most distant. The photons we are presently recording have travelled 11.7 billion years (lookback = light travel time). In the present epoch, its "comoving = proper distance" is nearly 22 Bly. Over the next few billion years, its redshift will gradually increase until the quasar becomes forever invisible. From the photons' perspective, travelling at the speed of light time does not pass, and their journey was instantaneous.
See the link for more information on ULX, IMBH and quasars:
www.cloudynights.com/articles/cat/articles/basic-extragal...
-Remote Takahashi TOA 150 x 1105mm
-OSC 36 x 300 sec, 2x drizzle, 50% linear crop
-Software:
DSS, XnView, StarNet++ v2, StarTools
Extragalactic Cosmological Calculator v2
www.cloudynights.com/gallery/image/123530-extragalactic-c...
An interesting group of galaxies, with the spiral to the mid right looking especially textured and perplexing. I'm not sure the one at the upper left is close enough to be one of the interacting objects. The two to the right seem the most likely to have made a pass at some point.
I'm curious whether the small spiral near the middle has any relationship or if it is in the background. It looks reddened in PanSTARRS data like it could be redshifted, but it also looks super dusty.
Color cutout from PanSTARRS can be found here:
ps1images.stsci.edu/cgi-bin/ps1cutouts?pos=12%3A41%3A03.8...
Data from the following proposal is used to create this image:
Establishing HST's Low Redshift Archive of Interacting Systems
All channels: ACS/WFC F606W
North is 16.37° clockwise from up.
Data from the following proposal is used to create this image:
Establishing HST's Low Redshift Archive of Interacting Systems
All channels: ACS/WFC F606W
North is 33.79° counter-clockwise from up.
NGC 4565 (Caldwell 38), Coma Berenices, (Needle Galaxy)
NGC 4565 is an edge-on spiral galaxy in the constellation of Coma Berenices, first documented by William Herschel in 1785. Due to its narrow profile, it is known as the Needle Galaxy. On large scales it is one of the nearest, biggest, and brightest members of the Coma I Galaxy Group. Considerable inconsistencies are found in the literature regarding the apparent and derived properties of this galaxy. According to the NED database, its blue apparent magnitude is 10.42 (8.21 V), and angular size 15.85 arcmin. Its redshift derived distance is 58.5 Mly, and distance based on the median value of 34 redshift-independent distance measurements is 38.47 Mly. Its redshift-based recession velocity is 1,259 km/s, and estimated diameter range between 177,000 and 268,000 light years. Although the galaxy is substantially larger than the Milky Way, its calculated intrinsic brightness is not proportionally higher. Due to its smaller surface area because of edge-on orientation and to thick layers of absorbing dust and gas, its integrated apparent magnitude and calculated absolute magnitudes are significantly lower than expected.
The galaxy's edge-on aspect obscures the nature of the central bulge in the optical band. Infrared studies with the Spitzer Space Telescope suggest the presence of a central bar as well as an inner ring. Meanwhile, the galaxy's orientation allows spectacular view of the dust lanes in the thin galactic disk. Spectroscopic studies of the central region indicate NGC 4565 has an active galactic nucleus of the LINER type powered by accretion around a central supermassive black hole.
NGC 4565 has at least two satellite galaxies. Slightly curved tips of its galactic disk suggest minor gravitational interaction. LEDA 2793674, lying in the foreground, is a small irregular dwarf, less than 10,000 ly in diameter. NGC 4562, in the background, is a minor barred spiral with a gravitationally distorted disk, about one quarter in diameter compared to the Milky Way.
Image details:
Meade 8'' ACF, AP 0.7x compressor (200 x 1400mm)
iEQ30pro mount, Orion 60mm f/4 SSAGpro autoguider
Canon T3i modified camera, Astronomik L3 filter
OSC 25 x 300 sec subexposures, iso 1600, 30 darks, 30 bias, 50% crop
Software: PHD2, DSS, XnView, StarNet++ v2, StarTools v1.3 and 1.7, Cosmological Calculator v3.
Model: Taylor Freeze
Photographer: Justin Bonaparte