View allAll Photos Tagged HCG
Le Quintette de Stephan*, regroupement visuel de cinq galaxies (NGC 7317, NGC 7318a, NGC 7318b, NGC 7319 et NGC 7320) dans la constellation de Pégase (Pegasus), est une énorme mosaïque (la plus grande image de Webb à ce jour, couvrant environ un cinquième du diamètre de la Lune avec plus de 150 millions de pixels et près de 1 000 fichiers image distincts) où les interactions galactiques ont probablement entraîné l'évolution des galaxies dans l'univers primitif. Des amas étincelants de millions de jeunes étoiles et des régions d'éclatement d'étoiles fraîches ornent l'image. Des queues balayées de gaz, de poussière et d'étoiles sont extraites de plusieurs galaxies en raison d'interactions gravitationnelles. Plus spectaculaire encore, Webb capture d'énormes ondes de choc alors que l'une des galaxies, NGC 7318b, traverse l'amas (cf. NASA et merci pour la photo).
*Édouard Stephan (1837-1923) est l'astronome français qui a observé pour la première fois ce quintette en 1878, en utilisant le terme de nébuleuses, personne n'imaginant alors qu'il s'agissait en réalité de galaxies, constituées de milliards d'étoiles et situées en dehors de la Voie lactée. Mais il meurt un an jour pour jour avant qu'Edwin Hubble en apporte la preuve en 1924 (cf. wikipédia).
Pour voir le Quintette (quartette !) de Stephan HCG 92 de Weeb avec les trois filtres de MIRI :
www.flickr.com/photos/7208148@N02/52212045542/in/datepost...
Pour voir les photos de Hubble en lumière visible (quintette et en dessous : NGC 7318 a et NGC 7318b en interaction) :
www.flickr.com/photos/7208148@N02/48834797768
www.flickr.com/photos/7208148@N02/48835169811/in/datepost...
Pour situer le Quintette de Stephan HCG 92 dans la constellation de Pégase (PEGASUS) :
www.flickr.com/photos/7208148@N02/48834796163/in/datepost...
Space can be a lonely place. But not so for this quartet of galaxies making up HCG 86 and observed here with ESO’s VLT Survey Telescope (VST). The four galaxies located approximately 270 million light years from Earth in the Sagittarius constellation, are seen from Earth as arranged in triangular shape, with three of them on a straight line and one underneath; the bright objects to the right of the elongated galaxy are not part of the quartet.
HCG stands for Hickson Compact Group, and is used to describe groups of four to ten galaxies where members are physically very close to each other. Because of their compactness, such groups are ideal environments to study galactic interactions, which can sometimes lead to galaxies merging with each other.
This image of HCG 86 was taken by a team of astronomers led by Rossella Ragusa of the Istituto Nazionale di Astrofisica in Italy as part of the VST Early-type Galaxy Survey (VEGAS) programme. “With VST we are able to investigate very faint structures in the galaxies' outskirts, which are the relics of past gravitational interactions and merging events,” says Ragusa. In particular, by mapping the light distribution in and around the group’s galaxies in this study, the team concluded that these faint structures are the leftovers of satellite galaxies gobbled by the group approximately seven billion years ago.
Located at ESO’s Paranal Observatory in Chile, the VST is one of the world’s largest survey telescopes, devoted to mapping the sky in visible light wavelengths. 2021 marks the anniversary of its first decade of operation, a period during which it has helped to search for planets outside the Solar System and probe the structure of our galaxy and the wider Universe.
Credit:
ESO/Ragusa, Spavone et al.
Happy Saturday, Flickrites! To celebrate our own version of "March Madness," we'll extend our postings to the weekends this month. To start us off, here's a glowing green beauty from Chandra, taken in 2001...
(From 2001) This Chandra image shows remarkable detail and complexity in the central region of the compact galaxy group known as HCG 62. Such galaxy groups, which contain fewer galaxies than the better-known galaxy clusters, are an important class of objects because they may serve as cosmic building blocks in the large-scale structure of the universe. After galaxies themselves form in the early universe, such groups of galaxies may be the next systems to evolve. Later, it is believed, these groups of galaxies may combine with each other to form the bigger galaxy clusters. Most galaxies in the present-day universe are still in groups or poor clusters. Our own Milky Way Galaxy, along with about two dozen other galaxies, including the Andromeda Nebula (M31) and the Large and Small Magellanic Clouds, is part of a galaxy group known as the Local Group.
A team of scientists, led by Jan Vrtilek (Harvard-Smithsonian Center for Astrophysics), observed HCG 62 with Chandra for about 50,000 seconds with the Advanced CCD Imaging Spectrometer. The range of X-ray surface brightness is represented in this image by various colors: green depicts the lower-brightness regions while purple and reddish indicate increasing X-ray intensity. The image is about four minutes of arc on a side, with north to the top and east to the left.
Chandra is an excellent tool to study the intragroup gas (the material between the galaxies) since this medium is too hot (roughly ten million degrees Celsius) to emit any significant radiation at optical wavelengths, but instead radiates most strongly in X-rays. Chandra also offers by far the highest angular resolution of any X-ray telescope to date, which is essential for showing the detailed structure of a complex source such as HCG 62. Hence, this X-ray observation provides a unique window for determining the physical characteristics of the galaxy group. Perhaps the most striking features of this X-ray image of HCG 62 are the two cavities that appear nearly symmetrically opposite one another (upper left and lower right) in the hot, X-ray emitting gas. These cavities might be explained by the presence of X-ray absorbing material, but are more likely due to jets of particles recently emitted from the core of NGC 4761, the central elliptical galaxy of HCG 62, although no such jets are visible today.
Full caption/images: chandra.harvard.edu/photo/2001/hcg62/
Image credit: NASA/CfA/J. Vrtilek et al.
Read more about Chandra:
p.s. You can see all of our Chandra photos in the Chandra Group in Flickr at: www.flickr.com/groups/chandranasa/ We'd love to have you as a member!
_____________________________________________
These official NASA photographs are being made available for publication by news organizations and/or for personal use printing by the subject(s) of the photographs. The photographs may not be used in materials, advertisements, products, or promotions that in any way suggest approval or endorsement by NASA. All Images used must be credited. For information on usage rights please visit: www.nasa.gov/audience/formedia/features/MP_Photo_Guidelin...
Back in Hull General Cemetery, every time I go with my camera something has changed the volunteers have found something new yet the trees and undergrowth claim the graves. Taken 21 January 2020 in Monochrome
Stephan's Quintet, (HCG 92, Arp 319), NGC 7320 Galaxy Group, Pegasus
This tight visual grouping of five galaxies was discovered in 1877 by Edouard Stephan at the Marseilles Observatory with the revolutionary 80 cm Foucault reflector, which was among the first to use a mirror of silvered glass, instead of speculum metal. The Quintet is the first compact group of galaxies ever documented. It has been carefully studied by numerous observatories ever since because it shows three galaxies in the process of merging, NGC7318-A, NGC7318-B, and NGC7319. All three appear to be barred spiral galaxies, severely distorted by tidal interactions. All display elongated and disrupted spiral arms, faint tidal tails of stars and gas drawn out from the galaxies into intergalactic space, and numerous bright blue regions of countless new stars ignited by gravitational perturbations of hydrogen clouds. Hubble's multi-band images in visible and infrared light reveal stellar populations of several age groups, indicating that starburst activity occurred in different epochs over hundreds of millions of years. In the long run, after billions of years, the three galaxies are destined to merge into a single giant elliptical galaxy. Based on their redshifts, and assuming Hubble Flow, the three galaxies lie at light travel distances between 267 and 312 million light years. However, they are probably much closer together. Due to strong gravitational interaction, they must have high peculiar velocities through space, which renders their distance estimates based on Hubble Flow unreliable.
www.cloudynights.com/articles/cat/articles/basic-extragal...
The fourth galaxy in the group is a modest elliptical galaxy, NGC 7317, gravitationally bound to its companions, but so far morphologically unaffected. These four galaxies are also gravitationally bound to the distant members of the Deer Lick Group, from which they are separated by only 35 arcmin.
www.cloudynights.com/topic/802766-ngc-7331-deer-lick-gala...
The most prominent galaxy in Stephan's Quintet is NGC 7320, a bright dwarf unbarred spiral which is actually 8 times closer than the other members of the visual grouping, and is gravitationally unbound to them. Based on its measurable properties (redshift, apparent magnitude, and angular size), it lies at a light travel distance of 36.4 Mly, receding at 706 km/s due to Hubble Flow (the expansion of space). Its diameter is only about 25,000 ly, five times smaller than the Milky Way's, and absolute magnitude some twenty times fainter. Blue color indicates a high star formation rate and a profusion of large, young, and very hot stars.
The most distant galaxy in the field is 2MFGC 17021, a large edge-on spiral, approximately the same size as the Milky Way, but about twice as bright. It is 784 Mly distant, receding at 17,113 km/s.
Image Details:
-Remote Takahashi TOA 150 x 1105 mm
-Paramount GT GEM
-25 x 300 sec subs, OSC, 2x drizzle, 50% linear crop
-Software: DSS, XnView, StarTools v 1.3 and 1.7, Cosmological Calculator v 2
Aircraft: ATR 72-212A
Operator: Flyways Linhas Aéreas
Location: Aeroporto Internacional de Florianópolis - SBFL
Registration: PR-TKN
Serial Number: 580
Year Built: 1998
Ex: F-WWEC, EC-HCG
Scottish Ambulance Service
Special Operations Response Team
Mitsubishi Shogun
A90
Hillfield Flyover
Inverkeithing
Volvo B8R / Plaxton Leopard YX17 OHW + Volvo B9TL / Wright Eclipse Gemini 2 BF63 HCG parked at the Plaxton Coach Centre, South Anston, 17/10/20
28 x 4-minute ISO 1600 auto-guided exposures.
Modified EOS 600D & Revelation 12" f/4 Newtonian reflector telescope.
Frames stacked in Deep Sky Stacker software. Result post-processed to increase contrast, reduce noise, adjust overall colour balance and reduce colour gradients caused by light pollution. Also Starnet++ software used to temporarily separate the stars from the subject and prevent them bloating when galaxy contrast was stretched.
Stephan's Quintet, (HCG 92, Arp 319), NGC 7320 Galaxy Group, Pegasus
This tight visual grouping of five galaxies was discovered in 1877 by Edouard Stephan at the Marseilles Observatory with the revolutionary 80 cm Foucault reflector, which was among the first to use a mirror of silvered glass, instead of speculum metal. The Quintet is the first compact group of galaxies ever documented. It has been carefully studied by numerous observatories ever since because it shows three galaxies in the process of merging, NGC7318-A, NGC7318-B, and NGC7319. All three appear to be barred spiral galaxies, severely distorted by tidal interactions. All display elongated and disrupted spiral arms, faint tidal tails of stars and gas drawn out from the galaxies into intergalactic space, and numerous bright blue regions of countless new stars ignited by gravitational perturbations of hydrogen clouds. Hubble's multi-band images in visible and infrared light reveal stellar populations of several age groups, indicating that starburst activity occurred in different epochs over hundreds of millions of years. In the long run, after billions of years, the three galaxies are destined to merge into a single giant elliptical galaxy. Based on their redshifts, and assuming Hubble Flow, the three galaxies lie at light travel distances between 267 and 312 million light years. However, they are probably much closer together. Due to strong gravitational interaction, they must have high peculiar velocities through space, which renders their distance estimates based on Hubble Flow unreliable.
www.cloudynights.com/articles/cat/articles/basic-extragal...
The fourth galaxy in the group is a modest elliptical galaxy, NGC 7317, gravitationally bound to its companions, but so far morphologically unaffected. These four galaxies are also gravitationally bound to the distant members of the Deer Lick Group, from which they are separated by only 35 arcmin.
www.cloudynights.com/topic/802766-ngc-7331-deer-lick-gala...
The most prominent galaxy in Stephan's Quintet is NGC 7320, a bright dwarf unbarred spiral which is actually 8 times closer than the other members of the visual grouping, and is gravitationally unbound to them. Based on its measurable properties (redshift, apparent magnitude, and angular size), it lies at a light travel distance of 36.4 Mly, receding at 706 km/s due to Hubble Flow (the expansion of space). Its diameter is only about 25,000 ly, five times smaller than the Milky Way's, and absolute magnitude some twenty times fainter. Blue color indicates a high star formation rate and a profusion of large, young, and very hot stars.
The most distant galaxy in the field is 2MFGC 17021, a large edge-on spiral, approximately the same size as the Milky Way, but about twice as bright. It is 784 Mly distant, receding at 17,113 km/s.
Image Details:
-Remote Takahashi TOA 150 x 1105 mm
-Paramount GT GEM
-25 x 300 sec subs, OSC, 2x drizzle, 30% linear crop
-Software: DSS, XnView, StarTools v 1.3 and 1.7, Cosmological Calculator v 2
Man NL253 Neoman Lion's City Hibrid propietat de Man
El veiem el 12 Febrer del 2004 fent proves al servei urbà de Granollers (Barcelona) de Transports Municipals de Granollers del Grup Sagalés. La fotografía feta al terme municipal de Canovelles
Aquet cotxe está fent proves a diferents empresas del país.
La semana anterior a la fotografía ho va fer a Manresa Bus de Manresa (Barcelona)
PGC35609 (also designated as HCG 56e) is a faint galaxy located in the constellation Ursa Major.
Position: It is located near the much larger and brighter warped spiral galaxy NGC 3718
Coordinates
Right Ascension: 11h 32m 32.7s
Declination: +52° 56' 21"
Magnitude: 15.4
425 million light-years away
MCV eVoRa bodied Volvo B8RLE, new to South West Coaches, Wincanton, in July 2022.
Seen on a route 81 service from South Petherton.
Autobus Man NL253 Neoman Lion's City híbrid fent provas a TMESA (Grupo Avanza ) de Terrassa (Barcelona)
Fotografiat a Terrassa (Barcelona) el 19 Setembre 2015
Aquet vehicle es propietat de Man
Anteriorment i que tinguem constancia a estat a aquestas empresas
EX - 301 Valladolid --> EX - 780 San Sebastián ---> EX - Rosanbus (B) sep'11 --> EX - Córdoba (sep'12) --> EX - Framar -GR- (dic'12) --> EX - 159 Interbus "M" (Mar'13) --> EX - TCC-Pamplona (jun'13) --> EX - Segovia (sep'13) --> EX - Alicante (Masatusa) oct'13 --> EX - 89 Zaragoza (nov'13) --> EX - Vigo (PO) abr'14 ---> EX - Grup Sagales (Urbà Granollers--> Urbà Mollet --> Urbà Manresa.) --> EX - Avila Bus (AV) nov'14 --> EX - Coop.Interurbana Andorrana (AD) feb'15
Pel Grup Sagalés ha pasat en dues vegades
Go Coachhire of Ottford Alexander R Volvo Olympian OLY-57 S869 HCG 8601 is seen here at the High Floor Buses Running Day at ASDA Gillingham Pier on 31/12/16.
Alexander R Volvo Olympian OLY-57 S869 HCG 8601
Back in Hull General Cemetery, every time I go with my camera something has changed the volunteers have found something new yet the trees and undergrowth claim the graves. Taken 21 January 2020 in Monochrome
No.12 in the Transabus fleet is 7301 HGC, a 2011 delivery. Sunsundegui Astral coachwork is carried by the B12M artic, seen In Palma centre.
Edited Hubble Space Telescope image of the Hickson Compact Group (No. 40) of galaxies. Color/processing variant.
Original caption: The NASA/ESA Hubble Space Telescope is celebrating its 32nd birthday with a stunning look at an unusual close-knit collection of five galaxies, called the Hickson Compact Group 40. This snapshot reflects a special moment in their lifetimes as they fall together before they merge.
Man 24.480 HOCL Noge Touring III (8396 HCG) de TGP d'Plesa de Montserrat (Barcelona) -Grup Direxis-
Matriculat el 16/03/2011
VIN: WMAR37ZZ2BC015693
El veiem el 4 Desembre 2023 a la Avda.Meridiana amb Fabra i Puig de Barcelona fent un servei escolar
Ex - Autocars Pons (Els Alamús -L-)
A 310 millions d'années-lumière de la Terre, dans la constellation de l'Hydre femelle (Hydra), Hickson Compact Group 40 (HCG 40) comprend trois galaxies en forme de spirale, une galaxie elliptique et une galaxie lenticulaire (en forme de lentille). Ces différentes galaxies se sont croisées au cours de leur évolution pour créer un échantillon de galaxies exceptionnellement peuplé et éclectique. Ces galaxies interagissent gravitationnellement en raison de la présence de beaucoup de gaz chauds. Dans environ un milliard d’années, elles finiront par entrer en collision et fusionner pour former une galaxie elliptique géante.
Sur la centaine de groupes de galaxies compactes de ce type qui ont été cataloguées à ce jour, le plus connu est le Quintette de Stephan HCG 92, à 270 millions d'années-lumière de la Terre dans la constellation de Pégase (Pegasus). Le sextette de Seyfert HCG 79, dans la constellation de la tête du Serpent (Serpens Caput) à 200 millions d'années-lumière de la Terre, ne contient en fait que cinq galaxies en interaction (cf. NASA, ESA, STScI, traitement de l'image : Alyssa Pagan STScI).
Pour situer les cinq galaxies Hickson Compact Group 40 (HCG 40) dans la constellation de l'Hydre femelle (Hydra) :
HCG 56 (Hickson Compact Group 56) is comprised of 5 galaxies at magnitudes 15-16.
11 x 4-minute, manually guided exposures at f/4 and ISO 1600. Modified EOS 600D & Revelation 12" Newtonian reflector telescope.
Registered and stacked using DeepSkyStacker; curves adjusted in Canon Photo Professional; noise reduction via Cyberlink PhotoDirector.
Hickson 44 Compact Galaxy Group, Leo Quartet ( NGC 3190 Group, Arp 316 )
In 1982, Canadian astronomer Paul Hickson published a study of 100 compact galaxy groups visible from the northern hemisphere. The best known entries are Copeland's Septet (57), Seyfert's Sextet (79), Stephan's Quintet (92)
ui.adsabs.harvard.edu/abs/1982ApJ...255..382H/abstract
Kinematic studies suggest that such crowded clusters are dynamically dominated by immense halos of dark matter where each member galaxy forms within its own subhalo, or a dark matter overdensity. Since the galaxies are gravitationally tightly bound, they manifest strong tidal interactions in the form of morphological deformation, elevated star formation rates, active galactic nucleus activity, and galaxy mergers. It is expected that the ultimate destiny of such groups is a merger into giant elliptical galaxies.
Unfortunately, most of these groups are too distant, small, and featureless to be of aesthetic interest in modest telescopes. Hickson Compact Group 44 (HCG 44) is a rare exception. It is composed of NGC 3190 (NGC 3189 is the SW region of this galaxy) which is a deformed edge-on spiral, elliptical galaxy NGC 3193, a deformed spiral NGC 3185, and a highly deformed spiral NGC 3187 whose light-blue color indicates abundant starburst activity. Irregular dwarf galaxy LEDA 86788 is probably a distant member of the group, but not presently interacting. Measurable and derived properties of the group members are presented in the chart below.
The last four galaxies in the chart are large and luminous, lying at light travel distances between 1.5 and 2.9 billion light years. Their measured angular sizes and derived actual diameters are probably larger than listed because the full extent of their faint peripheral sectors is not recordable.
Image Details:
Meade 8'' ACF, AP 0.7x compressor, 200 x 1400 mm
iEQ30pro mount, Orion 60mm f/4 SSAGpro autoguider
Canon T3i modified camera, Astronomik L3 filter
24 x 300 sec subs (11 discarded), iso 1600, 30 darks, 30 bias, 2x drizzle, 40% linear crop
Software: PHD2, DSS, XnView, StarNet++, StarTools.
Extragalactic Cosmological Calculator v 2 (freeware) information, download links, and sourcecode:
www.cloudynights.com/gallery/image/123530-extragalactic-c...