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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.
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
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.
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.
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.
Kind of a squid shaped galaxy merger. Can't seem to make out the second galaxy interacting with it, assuming there were at least two galaxies here originally. They are far enough along that they are nearly one. There are probably two galactic nuclei in there somewhere.
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 26.70° counter-clockwise from up.
Model: Taylor Freeze
Photographer: Justin Bonaparte
I'm not really sure what is going on here, but have come to expect that with Prop15446 galaxies. The smaller galaxy seems drawn toward the larger one, but I wonder whether it has already made its first pass of the more massive galaxy. There is a curious scattering of loose stars directly across from the small galaxy on the other side of the larger one.
A ground-based color view from the DECaLS viewer is here: legacysurvey.org/viewer?ra=174.4351&dec=47.8932&z...
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 1.62° counter-clockwise from up.
It's hard to find a spiral with arms this long. Depending on what you're willing to count as a single arm, one of them seems to wrap around almost two times. Upon realizing this I searched around for some other galaxies with more wraps, but couldn't seem to find any with distinct arms. Malin 1 comes to mind, but it's hard to read.
If anyone has any other galaxies with arms similar to this one, let me know.
A color image comprised of DES DR1 data is available:
legacysurvey.org/viewer?ra=351.9539&dec=-47.3811&...
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 29.01° 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.
Very pretty pair of interacting spiral galaxies.
There's a color view available from the ground-based Legacy Survey here: legacysurvey.org/viewer?ra=122.8032&dec=25.2003&z...
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 13.19° 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...
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 9.48° clockwise from up.
Interesting faint arm or tidal stream feature encircling this one like a halo. Looking at DSS data to see the surrounding sky, I don't see any obvious interaction partners. I suppose this is a late stage of some kind of interaction, and all galaxies involved have now merged. I wonder if some kind of small, diffuse galaxy could interact in such a way that it got pulled around nearly into a circle like this. If that were the case, then this would be more of a middle stage than an end stage. Anyway, that's just a lot of speculation.
I was interrupted in the middle of processing this by a rather large earthquake.
Establishing HST's Low Redshift Archive of Interacting Systems
All Channels: ACS/WFC F606W
North is 6.4° counter-clockwise from up.
An apparently disk-shaped, clumpy galaxy with a bit of star formation going on. The hook at one end is interesting.
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 10.80° clockwise from up.
Quite a long galaxy, stretched out due to some kind of recent interaction. Exactly what, I'm not sure. A rather large, diffuse filter ghost (faint, slightly brighter annular feature) is overlapping the right side of the image. There are two bright stars flanking this galaxy to the east or west. Either one could be the culprit, though I think the one to the west was responsible.
Check the widefield view out at the Legacy Survey to get a better view of the situation: legacysurvey.org/viewer?ra=7.1450&dec=-11.5858&la...
Establishing HST's Low Redshift Archive of Interacting Systems
(I might have hit this one too hard with the noise reduction. It looks funny.)
All Channels: ACS/WFC F606W
North is 59.33° counter-clockwise from up.
19-4-2021 Messier 63 or M63, also known as NGC 5055 or the seldom-used Sunflower Galaxy, is a spiral galaxy in the northern constellation of Canes Venatici with approximately 400 billion stars.
Distance to Earth: 27 million light years
Distance: 29.3 Mly (8.99 Mpc)
Apparent size (V): 12′.6 × 7′.2
Group or cluster: M51 Group
Redshift: 484 km/s
Constellation: Canes Venatici
39 light frames 32 dark frames 180sec's iso800.
Nikon D750-Nikon600mm Fl f4 prime & Nikon 2x teleconverter on SWNEQ6-R-Pro mount PHD2 guide- deepsky stacker - Photoshop, bortle 4.
Seen here in incredible detail, thanks to the NASA/ESA Hubble Space Telescope, is the starburst galaxy formally known as PLCK G045.1+61.1. The galaxy, which appears as multiple reddish dots near the center of the image, is being gravitationally lensed by a cluster of closer galaxies, also seen in the image.
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, creating stretched, magnified and sometimes multiple images of the lensed object. This effect was first predicted by Einstein’s general theory of relativity.
From 2009 to 2013, the European Space Agency’s Planck space observatory captured multiple all-sky surveys. In the course of these surveys, with complementary observations by the Herschel Space Observatory, Planck discovered some of the brightest gravitationally lensed, high-redshift galaxies in the night sky.
It was during the study of these Planck-Herschel selected sources using Hubble that the optical starlight emitted from this ultra-bright galaxy was found.
For more information: www.nasa.gov/image-feature/goddard/2020/hubble-makes-a-br...
Text credit: ESA (European Space Agency)
Image credit: ESA/Hubble & NASA, B. Frye
Sometimes the detector just isn't quite big enough. Two spirals; one fell off the edge. The telescope seems to have been preferentially pointed towards the more irregularly shaped spiral. Did the southern galaxy pass by the northern one recently and pull on its arms to get it this way, or was there something we can no longer see?
The southern galaxy looks so regular that I would doubt it interacted with anything recently if I saw it by itself.
Maybe there wasn't any interaction. Maybe that's just how they're both shaped.
Establishing HST's Low Redshift Archive of Interacting Systems
All Channels: ACS/WFC F606W
North is 35.34° clockwise from up.
Stellar streams looping around a disturbed spiral galaxy with a bit of dust and star formation evident. A widefield view shows barred spiral galaxy NGC 7682 just to the east. NGC 7682 seems relatively undisturbed by comparison, so one wonders if the two have anything to do with one another.
Check the color widefield view from Legacy Survey here: legacysurvey.org/viewer?ra=352.1989&dec=3.5200&la...
Establishing HST's Low Redshift Archive of Interacting Systems
All Channels: ACS/WFC F606W
North is 50.87° counter-clockwise from up.
This view reminds me somewhat of a smaller Coma Cluster, with smooth galaxies of varying shape and size gathered together. Most eye-catching is the large, irregularly shaped galaxy with features shaped by tidal forces and dust lanes crossing it at multiple angles.
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 23.06° clockwise from up.
A golden egg floats above its pedestal. Here an assumed spiral galaxy has been strangely transformed in a way that makes it difficult to recognize. Its nucleus is now off center—way off center—and its arms are disorganized, forming a kind of irregular ring. The golden egg is an elliptical galaxy which is the major participant in this process.
Turned 90° clockwise I think the composition looks remarkably like a phoenix with its egg.
Some color data is available from the PanSTARRS survey: ps1images.stsci.edu/cgi-bin/ps1cutouts?pos=Apg+141&fi...
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 2.49° counter-clockwise from up.
I'm a bit bothered by the cropping on this one, but otherwise it is a nice pair of interacting galaxies and some tidal tails.
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 128.30° 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 21.51° counter-clockwise from up.
NGC 2146 is a disrupted barred spiral galaxy in the constellation of Camelopardalis. It was discovered in 1876 by German astronomer Friedrich Winnecke, who was known for his work on comets, asteroids, and double stars. The galaxy is classified as SB(s)ab pec, indicating a barred spiral galaxy with tightly wound arms, and no ring around the central bulge. The "pec" descriptor refers to the "peculiar" appearance of the spiral arms, one of which is markedly stretched and inclined to the galactic plane by nearly 45*. Very high star formation rate (SFR) and densities within both spiral arms resembling large stellar trails suggest the galaxy recently merged with one or two substantial dwarf satellites, and is presently reforming into a larger object. Some sources suggest that NGC 2146 may have interacted with a nearby small galaxy, NGC 2146a, however that seems unlikely because the small galaxy's spiral structure appears quite well preserved. Aside from its disrupted aspect and starburst activity, NGC 2146 is also distinctive due to its conspicuous dust lanes extending across the background glow of the galactic core. Spectroscopy of the central region reveals widening of spectral lines. This indicates a high velocity dispersion of the stars in the nucleus due to the presence of a central supermassive black hole (SMBH). Absence of an active galactic nucleus means thet the central SMBH is not presently accreting matter.
Assuming its measured redshift of 0.00298 is caused exclusively by the expansion of space (Hubble Flow), NGC 2146 would lie at a distance of 41.3 Mly. However, the median value of 16 redshift-independent distance measurements is 17.40 Mpc, or 56.72 Mly. The two distance estimates differ because the measured redshift actually results from the combined motion due to Hubble Flow and the object's "peculiar velocity" through space. When available in a statistically valid number of measurements, redshift-independent estimates are generally regarded as more accurate for nearby galaxies, closer than approximately 140 Mly. From the apparent magnitude and angular size, accepting the distance of 56.72 Mly, we can derive the galaxy's actual diameter of 97,000 ly and absolute magnitude of -20.64. NGC 2146 is some 20-30% smaller, and about 15% less bright than the Milky Way.
Chandra CXC HIPS X-ray sky survey (SIMBAD) shows numerous X-ray sources within the NGC 2146 core, in the spiral arms, and in its halo. While it is possible that some of the sources may be local to the Milky Way, clustering of the sources around NGC 2146 suggests that most are of extragalactic origin.
The most common mechanism for X-ray emission in astronomical objects involves very hot ionized gases at temperatures of millions to hundreds of millions Kelvin (K). Stellar coronas, especially in young blue giants, emit X-rays, though they are regarded as relatively weak sources. Stronger emissions come from "X-ray binaries", "cataclysmic variable stars", supernova remnants, and hot gas clouds around stellar nurseries. Still stronger localized X-ray emissions are "ultra-luminous X-ray sources" or ULX. These are produced by actively accreting intermediate mass black holes (IMBH), usually identified in galactic disks, and by central supermassive black holes (SMBH) which define "active galactic nuclei" (AGN). By far the most powerful, but very diffuse, sources of X-rays are galaxy clusters.
While it is logical to expect numerous X-ray emissions in an actively merging starburst galaxy with accelerated stellar evolution, NGC 2146 has no identified ultra-luminous X-ray sources and no active galactic nucleus. This does not imply the galaxy contains no intermediate or supermassive black holes, but merely that they are not actively accreting.
On closer inspection, the attached image records a number of small, faint background galaxies, but only two of these have identifiers associated with measurable data. Based on a subjective estimate of their angular size and apparent brightness, the rest probably lie at approximate distances between 1 and 2 Bly. The image also records a single quasar (QSO) at a light travel distance (lookback time) of 9.2 Bly.
The distinctly blue galaxy Gaia DR3 1140883127890416128 may belong to a class of special objects: "Blue Compact Dwarf" galaxies (BCDs), which are field dwarf galaxies with inexplicably high star formation rates. BCDs are rare local versions of the "Faint Blue Galaxies" (FBGs), the most common galaxy type at redshifts between 0.1 and 2, but which are undetectable with small instruments. I estimate the apparent magnitude of this object around 20.5 and angular size at 0.15 arcmin. Unfortunately, no redshift information or color photometry is available in extragalactic databases, and the suspected nature of this galaxy can not be confirmed. For additional details on BCDs and FBGs please see section 32, Dwarf Galaxies, subsections 6 and 7 here:
www.cloudynights.com/articles/cat/articles/basic-extragal...
Image Details:
Remote Takahashi TOA 150x1105 mm
OSC 31x300 sec, 2x drizzle, 40% linear crop, 26x17'
Software:
DSS, XnView, StarNet++ v2, StarTools v1.8
Extragalactic Cosmological Calculator v2
www.cloudynights.com/gallery/image/123530-extragalactic-c...
Stephan's Quintet in the constellation Pegasus is a visual grouping of five galaxies of which four form the first compact galaxy group ever discovered. The brightest member of the visual grouping is NGC7320. These galaxies are of interest because of their violent collisions. Four of the five galaxies in Stephan's Quintet form a physical association -,Hickson Compact Group 92.
NGC 7320 (to the lower left of the group) indicates a small redshift (790 km/s) while the other four exhibit large redshifts (near 6600 km/s). Since galactic redshift is proportional to distance, NGC 7320 is only a foreground projection and is ~39 million ly from Earth versus the 210-340 million ly of the other five. (Text source Wikipedia)
Planewave 17” Corrected Dall-Kirkham Astrograph f/4.5, FLI-PL6303E CCD – Remotely imaged T21 Mayhill New Mexico
35 mins Luminance, 5mins R, G & B Image Cropped
In 2012, astronomers used the Hubble Space Telescope to revisit the Hubble Ultra Deep Field, peering even deeper than before at the near-infrared light of the cosmos. Astronomers use infrared light to study the distant universe because the expansion of space stretches wavelengths of light toward the red end of the electromagnetic spectrum, a phenomenon called "redshift."
The result was the Hubble Ultra Deep Field 2012. The observations uncovered a previously unseen population of seven primitive galaxies that formed more than 13 billion years ago, when the universe was less than 3 percent of its present age, or about 450 million years after the Big Bang.
The Hubble Ultra Deep Field 2012 was followed by the Hubble Ultra Deep Field 2014, which added ultraviolet light observations to obtain a more comprehensive view of this area in the constellation Fornax.
For an image of the Hubble Ultra Deep Field 2014, visit: hubblesite.org/contents/media/images/2014/27/3380-Image.html
Credit: NASA, ESA, R. Ellis (Caltech), and the UDF 2012 Team
For more information about this image, visit: hubblesite.org/contents/news-releases/2012/news-2012-48.h...
Fabulous pair of interacting galaxies. Wish I had color data.
Establishing HST's Low Redshift Archive of Interacting Systems
All channels: ACS/WFC F606W
North is 1.37° counter-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).
Below the event horizon, nothing, not even light, can escape.
Black hole is a fascinating and mind boggling subject that I know little about. You can find some elementary description in Wiki.
Arp 297 is a group of four interacting galaxies.
NGC 5754 is the large spiral and NGC 5752 is the smaller galaxy to the upper right. NGC 5754's internal structure has hardly been disturbed by the interaction while NGC5752 exhibits a long tidal tail. NGC5755 is the galaxy located to the left and NGC 5753 is in the 10 oclock position from NGC5755. Arp 297 is located in the constellation Boötes some 200 million light-years away. Detailed information can be found at arijmaki.wordpress.com/2011/11/09/ngc-5754-galaxy-with-hi...
Image Taken: 3 -5 June 14
Imaging scope: AT8RC CCDT67 1200mm
Imaging camera: Trius SX-694
Lights: Lum: 30 x 600 sec bin 1x1
Calibration: Flats, Bias
Guide scope: OAG Lodestar
Other details: Captured with SGP, guided with PHD, stacked in DSS processed in Photoshop
A soft and smooth disk of a galaxy with some arms that are both well-defined and impossible to circumscribe as they blend into one another. One thin lane of dust is visible in front of the nucleus about a third of the distance from the center point to the edge, while another thin lane is just discernible close to the brightest part of the nucleus.
There is another galaxy off to the left which is much smaller and can be partially seen at the edge of the composition. The larger galaxy hardly seems perturbed at all by the smaller one, while the smaller one seems to pulled and stretched thin at its periphery.
A color image comprised of SDSS data can be seen here:
legacysurvey.org/viewer?ra=130.6761&dec=14.2769&z...
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 13.51° clockwise from up.
M88 is a active spiral galaxy (Seyfert type 2)
M91 (left) is a barred spiral galaxy . Both are located 50-60 Mio light-years.
Many more distant galaxies are visible in this FOV , I checked only one near the bottom left IC3523 , redshift is 0.0739 or a distance of 1.02 Bio lightyears.
The image was recorded in 12 hours in August 2024 at my remote observatory in Hakos-Namibia with a SW Esprit 120ED , ZWO ASI2600MC camera on a 10 Micron 2000HPS mount
Tidal interaction between two galaxies. There seems to be a mini overlapper in the lower right corner. A nice, widefield color view is available at the Legacy Surveys Viewer: legacysurvey.org/viewer?ra=20.8636&dec=30.7820&zo...
Establishing HST's Low Redshift Archive of Interacting Systems
All Channels: ACS/WFC F606W
North is 21.04° counter-clockwise from up.
Just uploading a grayscale version of this so I can keep all the observations from this proposition organized better. The color version is here: flic.kr/p/2eGbVt7
Establishing HST's Low Redshift Archive of Interacting Systems
All Channels: ACS/WFC F606W
North is 45.34° counter-clockwise from up.