An extended emission-line region (EELR) are giant interstellar clouds ionized by the radiation of an active galactic nucleus (AGN) inside a galaxy or photons produced by the shocks associated with the radio jets.[1] An EELR can appear as a resolved cloud in relative nearby galaxies and as narrow emission lines in more distant galaxies.
EELRs were first discovered in radio galaxies. Usually the clouds emitting the narrow emission lines are restricted to a few kiloparsecs within the AGN, but some galaxies have narrow emission lines that extend a few kiloparsec to over 100 kiloparsecs. These clouds where therefore called extended emission-line regions (EELRs) and usually have a large doubly ionized oxygen [O III]/Hβ ratio, as well as a strong ionized helium He II/Hβ ratio (oxygen line at 5007 Å, helium line at 4686 Å). In some cases these EELRs show highly ionized species, such as calcium [Ca V] and iron [Fe VII] [Fe X].[2] Another common highly ionized species is the emission of neon [Ne V] (main line at 3426 Å).[3][4] This high level of ionization shows that the EELRs must be ionized by a mechanism related to the nucleus of the galaxy. HII regions do not show this high level of ionization.[2] The first [O III] images of EELRs were around galaxies, such as 3C 79,[5] 4C 37.43,[6] NGC 3516[7] or NGC 4151.[8]
In 2009 a large cloud was discovered that had similar spectral features as EELRs, but had no ionizing AGN nearby. It was concluded that the nearby galaxy IC 2497 hosted an AGN in the past. Today this AGN faded into inactivity. The hard ionizing radiation did however need time to travel the thousands of lightyears towards a cloud, which would later become Hanny's Voorwerp. This makes Hanny's Voorwerp the first EELR associated with a fading AGN. Previously EELRs were commonly first discovered via spectroscopy and required high-resolution imaging to further resolve the EELRs. Hanny's Voorwerp was however discovered in broad band imaging from the Sloan Digital Sky Survey.[3] This prompted a search for more EELRs in broad-band imaging surveys by galaxy zoo volunteers, who also discovered Hanny's Voorwerp. EELRs are called "Voorwerpjes" by the galaxy zoo members.[4] EELRs that are ionized by the AGN of a companion galaxy were also discovered. This type of ionization is called cross-ionization.[9]
In broad-band images the [O III] emission lines usually lie at the g-band. The true color of an EELR would be dominated by the [O III] emission, which is a cyan color. In astronomical imaging slightly false-color images that transform g, r and i bands into RGB-images are more common. Sometimes the i-band is replaced with a z-band image. The EELRs appear as blue (g-band) objects in these survey images. Sometimes the H-alpha line is redshifted enough to lie at the i-band, which can make the EELR appear as a blue-violet object in these survey images.[4] Sometimes the [O III] is redshifted enough that this line overlaps with the r-band or i-band, which makes them green or red in survey images of the Hyper Suprime-Cam.[10] At around 0.1<z<0.38 the 5006.843 Å [O III] line is redshifted to the r-band and at 0.38<z<0.68 it is redshifted to the i-band.[note 1]
Another related type of cloud is a extended narrow-line region (ENLR). The EELRs usually have dynamically chaotic structures and high velocities and are probably the result of mergers. ENLRs on the other hand follow the disk structure of the galaxy and have a low velocity.[10]
List of resolved EELRs
This is a list of EELRs with resolved [O III] images or other emission-lines
| Name Host galaxy | Image EELR | Distance to nucleus (kpc) | Date/Reference |
|---|---|---|---|
| MR 2251-178 | 
|
30-50 | 1990[12] |
| Centaurus A
outer and inner filaments |
|
7 & 16 | 1991[13] |
| IC 5063 | 
|
22 | 1991[14] |
| 3CR 368 | 45 | 1991[15] | |
| 3C 352 | 15.6 | 1992[16] | |
| NGC 4151 | 
|
1.16 | 1993[8] |
| NGC 3516 | 
|
4 | 1995[7] |
| 3C 273 | 
|
14.4 | 1996[17] |
| PKS 2250–41 | 
|
40-65 | 1997[18] |
| NGC 5643 | 
|
1.8 | 1997[19] |
| PKS 2356–61 | 25 | 1998[20] | |
| NGC 5256 | 
|
7 | 2000[21] |
| NGC 4388 | 
|
35 | 2002[22] |
| 4C 37.43 | 20 | 2002[23] | |
| 3C 171 | 
|
5 | 2003[24] |
| PKS 1932–46 | 100 | 2007[25] | |
| 3C 79 | 
|
2008[5] | |
| IC 2497 | 
|
40[4] | 2009[3] |
| 3C 48 | 2009[26] | ||
| Mrk 1014 | 
|
2009[26] | |
| 3C 249.1 | 2009[26] | ||
| Ton 616 | 2009[26] | ||
| Ton 202 | 2009[26] | ||
| PKS 2251+11 | 2009[26] | ||
| Mrk 78 | 
|
16 | 2012[4] |
| SDSS J095559.88+395446.9 | 
|
10 | 2012[4] |
| SDSS J100507.88+283038.5 | 
|
13 | 2012[4] |
| IC 2637 | 11 | 2012[4] | |
| NGC 3758 | 
|
17 | 2012[4] |
| UGC 7342 | 
|
38 | 2012[4] |
| NGC 5252 | 
|
21 | 2012[4] |
| Mrk 273 | 
|
19 | 2012[4] |
| Mrk 463 | 
|
16 | 2012[4] |
| Teacup galaxy | 
|
18 | 2012[4] |
| SDSS J151004.01+074037.1 | 
|
10 | 2012[4] |
| CGCG 077-117
(SDSS J152412.58+083241.2) |
|
19 | 2012[4] |
| NGC 5972 | 
|
33 | 2012[4] |
| Mrk 1498 | 
|
21 | 2012[4] |
| Mrk 883 | 
|
37 | 2012[4] |
| UGC 11185 | 
|
11 | 2012[4] |
| SDSS J220141.64+115124.3 | 
|
16 | 2012[4] |
| 3C 305 | 
|
2012[27] | |
| 3C 381 | 38 | 2013[28] | |
| NGC 7252 | 4 | 2013[29] | |
| ShaSS 073 | 
|
21 | 2018[30] |
| J023106−034513 | 30 | 2018[10] | |
| J083823+015012 | 29 | 2018[10] | |
| J090254+001116 | 10 | 2018[10] | |
| J091113+032604 | 10 | 2018[10] | |
| J092203−004443 | 13 | 2018[10] | |
| J155143+434758 | 11 | 2018[10] | |
| J162913+441442 | 15 | 2018[10] | |
| J220347+020443 | 12 | 2018[10] | |
| J220440+005232 | 8 | 2018[10] | |
| J224027+004347 | 9 | 2018[10] | |
| 3C 17 | 10.5 | 2019[31] | |
| 3C 18 | 13 | 2019[31] | |
| 3C 33 | 6.3 | 2019[31] | |
| 3C 63 | 30.1 | 2019[31] | |
| 3C 318.1 | 11.7 | 2019[31] | |
| 3C 327 | 8.1 | 2019[31] | |
| 3C 353 | 12.7 | 2019[31] | |
| 3C 386 | 4.2 | 2019[31] | |
| 3C 403 | 11.3 | 2019[31] | |
| 3C 424 | 2.4 | 2019[31] | |
| 3C 442 | 3 | 2019[31] | |
| 3C 445 | 17 | 2019[31] | |
| 3C 458 | 
|
80.2 | 2019[31] |
| 3C 459 | 69 | 2019[31] | |
| SDSS J002944.89+001011.1 | 2019[9] | ||
| SDSS J005754.03+012013.8 | 
|
2019[9] | |
| SDSS J083902.96+470756.3 | 2019[9] | ||
| Z 180–9 | 2019[9] | ||
| NGC 3341 | 
|
2019[9] | |
| UGC 6081 | 
|
2019[9] | |
| SDSS J120149.74-015327.5 | 2019[9] | ||
| SDSS J121418.25+293146.7 | 
|
2019[9] | |
| Arp 239 (NGC 5278/NGC 5279) | 
|
2019[9] | |
| SDSS J135429.05+132757.2 | 2019[9] | ||
| Mrk 1172 | 14 | 2021[32] | |
| NGC 235 | 26 | 2022[33] | |
| NGC 5514 | 75 | 2022[33] | |
| 3C 98 | 6 | 2022[34] | |
| 3C 135 | 31.6 | 2022[34] | |
| 3C 180 | 59.8 | 2022[34] | |
| 3C 196.1 | 9.3 | 2022[34] | |
| 3C 198 | 32.6 | 2022[34] | |
| 3C 227 | 
|
46.1 | 2022[34] |
| 3C 300 | 17.2 | 2022[34] | |
| 2MASS J08001609+2928172 | 2023[35] | ||
| Z 119–12 | 2023[35] | ||
| 2MASX J13020015+2746579 | 2023[35] | ||
| 2MASS J08152577+3720258 | 2023[35] | ||
| 2MASX J09515536+0329006 | 2023[35] | ||
| UGC 5941 | 2024[36] |
Notes
References
- ^ Best, P. N.; Röttgering, H. J. A.; Longair, M. S. (2000-01-01). "Ionization, shocks and evolution of the emission-line gas of distant 3CR radio galaxies". Monthly Notices of the Royal Astronomical Society. 311: 23–36. arXiv:astro-ph/9908211. doi:10.1046/j.1365-8711.2000.03028.x. ISSN 0035-8711.
- ^ a b Robinson, A.; Binette, L.; Fosbury, R. A. E.; Tadhunter, C. N. (1987-07-01). "Emission-line activity in radio galaxies". Monthly Notices of the Royal Astronomical Society. 227: 97–114. Bibcode:1987MNRAS.227...97R. doi:10.1093/mnras/227.1.97. ISSN 0035-8711.
- ^ a b c Lintott, Chris J.; Schawinski, Kevin; Keel, William; van Arkel, Hanny; Bennert, Nicola; Edmondson, Edward; Thomas, Daniel; Smith, Daniel J. B.; Herbert, Peter D.; Jarvis, Matt J.; Virani, Shanil; Andreescu, Dan; Bamford, Steven P.; Land, Kate; Murray, Phil (2009-10-01). "Galaxy Zoo: 'Hanny's Voorwerp', a quasar light echo?". Monthly Notices of the Royal Astronomical Society. 399 (1): 129–140. arXiv:0906.5304. Bibcode:2009MNRAS.399..129L. doi:10.1111/j.1365-2966.2009.15299.x. ISSN 0035-8711.
- ^ a b c d e f g h i j k l m n o p q r s t u Keel, William C.; Chojnowski, S. Drew; Bennert, Vardha N.; Schawinski, Kevin; Lintott, Chris J.; Lynn, Stuart; Pancoast, Anna; Harris, Chelsea; Nierenberg, A. M.; Sonnenfeld, Alessandro; Proctor, Richard (2012-02-01). "The Galaxy Zoo survey for giant AGN-ionized clouds: past and present black hole accretion events". Monthly Notices of the Royal Astronomical Society. 420 (1): 878–900. arXiv:1110.6921. Bibcode:2012MNRAS.420..878K. doi:10.1111/j.1365-2966.2011.20101.x. ISSN 0035-8711.
- ^ a b Fu, Hai; Stockton, Alan (2008-04-01). "The Host Galaxy and the Extended Emission-Line Region of the Radio Galaxy 3C 79". The Astrophysical Journal. 677 (1): 79–91. arXiv:0712.4145. Bibcode:2008ApJ...677...79F. doi:10.1086/529015. ISSN 0004-637X.
- ^ Fu, Hai; Stockton, Alan (2007-09-01). "Integral Field Spectroscopy of the Extended Emission-Line Region of 4C 37.43". The Astrophysical Journal. 666 (2): 794–805. arXiv:0705.4365. Bibcode:2007ApJ...666..794F. doi:10.1086/520530. ISSN 0004-637X.
- ^ a b Golev, V.; Yankulova, I.; Bonev, T.; Jockers, K. (1995-03-01). "New narrow-band imaging of the extended emission-line region in the Seyfert galaxy NGC 3516". Monthly Notices of the Royal Astronomical Society. 273 (1): 129–138. Bibcode:1995MNRAS.273..129G. doi:10.1093/mnras/273.1.129. ISSN 0035-8711.
- ^ a b Yoshida, Michitoshi; Ohtani, Hiroshi (1993-06-01). "A Study of the Extended Emission-Line Region of the Seyfert Galaxy NGC 4151 by Means of Narrow-Band Imaging Observations". Publications of the Astronomical Society of Japan. 45: 407–420. Bibcode:1993PASJ...45..407Y. ISSN 0004-6264.
- ^ a b c d e f g h i j k Keel, William C.; Bennert, Vardha N.; Pancoast, Anna; Harris, Chelsea E.; Nierenberg, Anna; Chojnowski, S. Drew; Moiseev, Alexei V.; Oparin, Dmitry V.; Lintott, Chris J.; Schawinski, Kevin; Mitchell, Graham; Cornen, Claude (2019-03-01). "AGN photoionization of gas in companion galaxies as a probe of AGN radiation in time and direction". Monthly Notices of the Royal Astronomical Society. 483 (4): 4847–4865. arXiv:1711.09936. Bibcode:2019MNRAS.483.4847K. doi:10.1093/mnras/sty3332. ISSN 0035-8711.
- ^ a b c d e f g h i j k l Sun, Ai-Lei; Greene, Jenny E.; Zakamska, Nadia L.; Goulding, Andy D.; Strauss, Michael A.; Huang, Song; Johnson, Sean D.; Kawaguchi, Toshihiro; Matsuoka, Yoshiki; Marsteller, Alisabeth A.; Nagao, Tohru; Toba, Yoshiki (2018-10-01). "Imaging extended emission-line regions of obscured AGN with the Subaru Hyper Suprime-Cam Survey". Monthly Notices of the Royal Astronomical Society. 480 (2): 2302–2323. arXiv:1803.07241. Bibcode:2018MNRAS.480.2302S. doi:10.1093/mnras/sty1394. ISSN 0035-8711.
- ^ Smith, J. Allyn; Tucker, Douglas L.; Kent, Stephen; Richmond, Michael W.; Fukugita, Masataka; Ichikawa, Takashi; Ichikawa, Shin-ichi; Jorgensen, Anders M.; Uomoto, Alan; Gunn, James E.; Hamabe, Masaru; Watanabe, Masaru; Tolea, Alin; Henden, Arne; Annis, James (2002-04-01). "The u'g'r'i'z' Standard-Star System". The Astronomical Journal. 123: 2121–2144. arXiv:astro-ph/0201143. doi:10.1086/339311. ISSN 0004-6256.
- ^ Macchetto, F.; Colina, L.; Golombek, D.; Perryman, M. A. C.; di Serego Alighieri, S. (1990-06-01). "The Structure and Ionization of the Extended Emission-Line Filaments Surrounding the QSO MR 2251-178". The Astrophysical Journal. 356: 389. Bibcode:1990ApJ...356..389M. doi:10.1086/168847. ISSN 0004-637X.
- ^ Morganti, R.; Robinson, A.; Fosbury, R. A. E.; di Serego Alighieri, S.; Tadhunter, C. N.; Malin, D. F. (1991-03-01). "The nature of the optical filaments in Centaurus A. Evidence for a beamed ionizing continuum". Monthly Notices of the Royal Astronomical Society. 249: 91. doi:10.1093/mnras/249.1.91. ISSN 0035-8711.
- ^ Colina, L.; Sparks, W. B.; Macchetto, F. (1991-03-01). "IC 5063: A Merger Remnant with a Hidden Luminous Active Nucleus". The Astrophysical Journal. 370: 102. Bibcode:1991ApJ...370..102C. doi:10.1086/169795. ISSN 0004-637X.
- ^ Hammer, F.; Le Fevre, O.; Proust, D. (1991-06-01). "Deep Spectroscopy under High Spatial Resolution of the High-Redshift Radio Source 3CR 368: The Monster Elucidated". The Astrophysical Journal. 374: 91. Bibcode:1991ApJ...374...91H. doi:10.1086/170099. ISSN 0004-637X.
- ^ Hippelein, Hans; Meisenheimer, Klaus (1992-10-01). "The extended line-emission from 3C 352". Astronomy and Astrophysics. 264: 472. Bibcode:1992A&A...264..472H. ISSN 0004-6361.
- ^ Hippelein, H.; Meisenheimer, K.; Roeser, H. J. (1996-12-01). "An emission line region associated with 3C 273". Astronomy and Astrophysics. 316: 29–32. Bibcode:1996A&A...316...29H. ISSN 0004-6361.
- ^ Clark, N. E.; Tadhunter, C. N.; Morganti, R.; Killeen, N. E. B.; Fosbury, R. A. E.; Hook, R. N.; Siebert, J.; Shaw, M. A. (1997-04-01). "Radio, optical and X-ray observations of PKS 2250-41: a jet/galaxy collision?". Monthly Notices of the Royal Astronomical Society. 286 (3): 558–582. Bibcode:1997MNRAS.286..558C. doi:10.1093/mnras/286.3.558. ISSN 0035-8711.
- ^ Simpson, Chris; Wilson, A. S.; Bower, Gary; Heckman, T. M.; Krolik, J. H.; Miley, G. K. (January 1997). "A One-sided Ionization Cone in the Seyfert 2 Galaxy NGC 5643". The Astrophysical Journal. 474 (1): 121–128. Bibcode:1997ApJ...474..121S. doi:10.1086/303466.
- ^ Koekemoer, Anton M.; Bicknell, Geoffrey V. (1998-04-01). "Dynamics and Excitation of Radio Galaxy Emission-Line Regions. I. PKS 2356-61". The Astrophysical Journal. 497 (2): 662–680. arXiv:astro-ph/9711229. Bibcode:1998ApJ...497..662K. doi:10.1086/305490. ISSN 0004-637X.
- ^ Ishigaki, Tsuyoshi; Yoshida, Michitoshi; Aoki, Kentaro; Ohtani, Hiroshi; Sugai, Hajime; Hayashi, Tadashi; Ozaki, Shinobu; Hattori, Takashi; Ishii, Motomi (2000-02-01). "Tridimensional Spectrophotometric Study of the Extended Emission-Line Regions of the Infrared-Luminous Merger Markarian 266". Publications of the Astronomical Society of Japan. 52: 185–207. Bibcode:2000PASJ...52..185I. doi:10.1093/pasj/52.1.185. ISSN 0004-6264.
- ^ Yoshida, Michitoshi; Yagi, Masafumi; Okamura, Sadanori; Aoki, Kentaro; Ohyama, Youichi; Komiyama, Yutaka; Yasuda, Naoki; Iye, Masanori; Kashikawa, Nobunari; Doi, Mamoru; Furusawa, Hisanori; Hamabe, Masaru; Kimura, Masahiko; Miyazaki, Masayuki; Miyazaki, Satoshi (2002-03-01). "Discovery of a Very Extended Emission-Line Region around the Seyfert 2 Galaxy NGC 4388". The Astrophysical Journal. 567 (1): 118–129. arXiv:astro-ph/0110473. Bibcode:2002ApJ...567..118Y. doi:10.1086/338353. ISSN 0004-637X.
- ^ Stockton, Alan; MacKenty, John W.; Hu, Esther M.; Kim, Tae-Sun (2002-06-01). "The Extended Emission-Line Region of 4C 37.43". The Astrophysical Journal. 572 (2): 735–745. arXiv:astro-ph/0205040. Bibcode:2002ApJ...572..735S. doi:10.1086/340432. ISSN 0004-637X.
- ^ Hardcastle, M. J. (2003-02-01). "Probing the extended emission-line region in 3C 171 with high-frequency radio polarimetry". Monthly Notices of the Royal Astronomical Society. 339 (2): 360–366. arXiv:astro-ph/0209612. Bibcode:2003MNRAS.339..360H. doi:10.1046/j.1365-8711.2003.06102.x. ISSN 0035-8711.
- ^ Inskip, K. J.; Tadhunter, C. N.; Dicken, D.; Holt, J.; Villar-Martín, M.; Morganti, R. (2007-11-01). "PKS1932-46: a radio source in an interacting group?". Monthly Notices of the Royal Astronomical Society. 382 (1): 95–108. arXiv:0708.2848. Bibcode:2007MNRAS.382...95I. doi:10.1111/j.1365-2966.2007.12378.x. ISSN 0035-8711.
- ^ a b c d e f Fu, Hai; Stockton, Alan (2009-01-01). "Extended Emission-Line Regions: Remnants of Quasar Superwinds?". The Astrophysical Journal. 690 (1): 953–973. arXiv:0809.1117. Bibcode:2009ApJ...690..953F. doi:10.1088/0004-637X/690/1/953. ISSN 0004-637X.
- ^ Hardcastle, M. J.; Massaro, F.; Harris, D. E.; Baum, S. A.; Bianchi, S.; Chiaberge, M.; Morganti, R.; O'Dea, C. P.; Siemiginowska, A. (2012-08-01). "The nature of the jet-driven outflow in the radio galaxy 3C 305". Monthly Notices of the Royal Astronomical Society. 424 (3): 1774–1789. arXiv:1205.0962. Bibcode:2012MNRAS.424.1774H. doi:10.1111/j.1365-2966.2012.21247.x. ISSN 0035-8711.
- ^ Reynaldi, V.; Feinstein, C. (2013-04-01). "Searching for evidence of jet-cloud interaction in radio galaxies. First results for 3C 381". Monthly Notices of the Royal Astronomical Society. 430 (3): 2221–2231. arXiv:1301.2216. Bibcode:2013MNRAS.430.2221R. doi:10.1093/mnras/stt042. ISSN 0035-8711.
- ^ Schweizer, François; Seitzer, Patrick; Kelson, Daniel D.; Villanueva, Edward V.; Walth, Gregory L. (2013-08-01). "The [O III] Nebula of the Merger Remnant NGC 7252: A Likely Faint Ionization Echo". The Astrophysical Journal. 773 (2): 148. arXiv:1307.2233. Bibcode:2013ApJ...773..148S. doi:10.1088/0004-637X/773/2/148. ISSN 0004-637X.
- ^ Merluzzi, Paola; Busarello, Giovanni; Dopita, Michael A.; Thomas, Adam D.; Haines, Chris P.; Grado, Aniello; Limatola, Luca; Mercurio, Amata (2018-01-01). "An Interacting Galaxy Pair at the Origin of a Light Echo". The Astrophysical Journal. 852 (2): 113. arXiv:1801.01005. Bibcode:2018ApJ...852..113M. doi:10.3847/1538-4357/aa9fff. ISSN 0004-637X.
- ^ a b c d e f g h i j k l m n Balmaverde, B.; Capetti, A.; Marconi, A.; Venturi, G.; Chiaberge, M.; Baldi, R. D.; Baum, S.; Gilli, R.; Grandi, P.; Meyer, E.; Miley, G.; O'Dea, C.; Sparks, W.; Torresi, E.; Tremblay, G. (2019-12-01). "The MURALES survey. II. Presentation of MUSE observations of 20 3C low-z radio galaxies and first results". Astronomy and Astrophysics. 632: A124. arXiv:1903.10768. Bibcode:2019A&A...632A.124B. doi:10.1051/0004-6361/201935544. ISSN 0004-6361.
- ^ Lassen, Augusto; Riffel, Rogério; Chies-Santos, Ana L.; Johnston, Evelyn; Haeussler, Boris; Dutra, Daniel R.; Azevedo, Gabriel M. (2021-01-01). "An Extended Emission Line Region around Mrk 1172". Galaxy Evolution and Feedback Across Different Environments. Proceedings of the International Astronomical Union. 359: 438–440. Bibcode:2021IAUS..359..438L. doi:10.1017/S1743921320004299.
- ^ a b Keel, William C.; Moiseev, Alexei; Kozlova, D. V.; Ikhsanova, A. I.; Oparin, D. V.; Uklein, R. I.; Smirnova, A. A.; Eselevich, M. V. (2022-03-01). "The TELPERION survey for distant [O III] clouds around luminous and hibernating AGN". Monthly Notices of the Royal Astronomical Society. 510 (3): 4608–4625. arXiv:2112.07084. Bibcode:2022MNRAS.510.4608K. doi:10.1093/mnras/stab3656. ISSN 0035-8711.
- ^ a b c d e f g Balmaverde, B.; Capetti, A.; Baldi, R. D.; Baum, S.; Chiaberge, M.; Gilli, R.; Jimenez-Gallardo, A.; Marconi, A.; Massaro, F.; Meyer, E.; O'Dea, C.; Speranza, G.; Torresi, E.; Venturi, G. (2022-06-01). "The MURALES survey. VI. Properties and origin of the extended line emission structures in radio galaxies". Astronomy and Astrophysics. 662: A23. arXiv:2204.00528. Bibcode:2022A&A...662A..23B. doi:10.1051/0004-6361/202142823. ISSN 0004-6361.
- ^ a b c d e French, K. Decker; Earl, Nicholas; Novack, Annemarie B.; Pardasani, Bhavya; Pillai, Vismaya R.; Tripathi, Akshat; Verrico, Margaret E. (2023-06-01). "Fading AGNs in Poststarburst Galaxies". The Astrophysical Journal. 950 (2): 153. arXiv:2304.10419. Bibcode:2023ApJ...950..153F. doi:10.3847/1538-4357/acd249. ISSN 0004-637X.
- ^ Keel, William; Moiseev, Alexei; Uklein, Roman; Smirnova, Aleksandrina (2024-03-01), The TELPERION survey for extended emission regions around AGN: a strongly-interacting and merging galaxy sample, arXiv:2403.04898, retrieved 2024-03-29
This page was last edited on 8 April 2024, at 03:38