Green bean galaxy

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J0113+0106.png
J1155-0147.png
These two images show the green bean galaxies J0113+0106 (top) and J1155−0147 (bottom) as seen by the Hyper Suprime-Cam on the Subaru Telescope.

Green bean galaxies (GBGs) are very rare astronomical objects that are thought to be quasar ionization echos. [1] [2] [3] They were discovered by Mischa Schirmer and colleagues R. Diaz, K. Holhjem, N.A. Levenson, and C. Winge. [1] The authors report the discovery of a sample of Seyfert-2 galaxies with ultra-luminous galaxy-wide narrow-line regions (NLRs) at redshifts z=0.2-0.6. [1]

Contents

While examining survey images taken with the 3.6-meter Canada–France–Hawaii Telescope (CFHT) atop 4200-m Mauna Kea, Hawaii, Schirmer noticed a galaxy with unusual colors—strongly peaking in the r filter, suggesting a spectral line. [1] [4] In fact, the color is quite similar to the Green Pea galaxies (GPs), which are compact star-forming galaxies. However, the object which became known as a GBG is much larger. [1] [5]

These galaxies are so rare that there is on average only one in a cube about 1.3 billion light-years across. [1] They were nicknamed GBGs because of their color and because they are superficially similar to, but larger than, GPs. [1] The interstellar gas in most GPs is ionized by UV-light from intense star formation, whereas the gas in GBGs is ionized by hard x-rays from an active galactic nucleus (AGN). The scarcity of GBGs indicates that this phenomenon is very rare, and/or very short-lived. [1]

GBGs are likely related to the object known as Hanny's Voorwerp, another possible quasar ionization echo. [6] GBGs are substantially different, though, as their luminosities, sizes and gas masses are 10-100 times higher than in other quasar ionisation clouds, for instance the 154 studied in Keel et al. 2012 (nicknamed 'voorwerpjes'). [7] These 'voorwerpjes' are estimated to have bright phases that last between ~20,000 and 200,000 years. [7]

Possible formation mechanisms are currently under investigation. Likely, the giant gas outflows have been produced during the last stages in the life of super-luminous quasars, which subsequently experienced a rapid shut-down, e.g. due to a process known as AGN feedback. [8] The escaping X-rays from the former very active quasar state still ionize the gas, causing the ionization echo.

Sloan Digital Sky Survey (SDSS) identifications

Green Bean Galaxies List (SDSS DR8 refs)
NumberSDSS idNotes
0011237679077517557845 GALEX All Sky Catalog (ASC) J002016.43-053127.1
0021237676441460474246GALEX ASC J002434.84+325842.5
0031237666091128914338GALEX ASC J011136.63+225357.5
00412376663408003647698 previous references listed in NED.
0051237680284389015833GALEX ASC J015930.73+270303.4
00612376503715552297742 previous references listed in NED, including CHANDRA 2010.
0071237661386529374363GALEX ASC J134709.11+545311.0
0081237662236402647262GALEX ASC J135155.51+081608.7
0091237665442062663827 NVSS J144110+251702
01012376557424078357911 previous reference in NED as part of a compact group (similar to HCGs).
0111237662306730639531GALEX ASC J150420.75+343958.6
0121237667968032637115NVSS J150517+194450
0131237669699436675933NVSS J205057+055014
0141237680191506678389NVSS J213542-031432
0151237680306395415794GALEX ASC J220216.57+230904.8
0161237656538051248311Prototype GBG J2240-0927, GALEX ASC J224024.09-092748.5
0171237680503434445439SDSS J230829.37+330310.4

VLT/XSHOOTER spectrum of Green Bean Galaxy J2240-0927

The spectrum of Green Bean Galaxy J2240 Spectrum of Green Bean Galaxy J2240.jpg
The spectrum of Green Bean Galaxy J2240

On the left is the spectrum of the astronomical object J224024.1-092748 (hereafter: J2240). [1] It was acquired using the Very Large Telescope and XSHOOTER, a multi wavelength (300-2500 nm) medium resolution spectrograph. The J2240 spectrum shows 3 bandwidths: UVB (Ultraviolet B which are medium UV wavelengths of 315–280 nm), VIS (the visible spectrum) and NIR (Near Infrared, which have wavelengths of 0.75–1.4 μm).

In the spectrum of J2240, the black line represents the galaxy center, integrated to within ±4.5 kpc (kilo-parsec) of the nucleus, while the blue line has been integrated over 7.6 kpc, centered on the ionized cloud. Note the great similarity between the two spectra. [1] For visualization purposes, data has been filtered with a 0.7 nm-wide median kernel. Thus the actual resolution is 48 (UVB/VIS) and 12 (NIR) times higher than shown for the UVB/VIS and (NIR) channels respectively. [1]

Unravelling the emission signature of a quasar ionization echo

A Green bean galaxy named J224024.1-092748 (abbreviation J2240) A Green-bean Galaxy.jpg
A Green bean galaxy named J224024.1−092748 (abbreviation J2240)

In May 2015, a study was accepted for publication in MNRAS titled: "The "Green Bean" Galaxy SDSS J224024.1--092748: Unravelling the emission signature of a quasar ionization echo." [9]

The abstract states: "'Green Bean' galaxies (GBs) are the most [O III]-luminous type-2 active galactic nuclei (AGN) at z ˜ 0.3. However, their infrared luminosities reveal AGN in very low activity states, indicating that their gas reservoirs must be ionized by photons from a recent high activity episode – we are observing quasar ionization echoes." Further on: "Our analysis of J224024.1-092748 indicates that GBs provide a unique fossil record of the transformation from the most luminous quasars to weak AGN." [9]

AGN ionization echoes, thermal echoes, and ionization deficits

In July 2016, a study was accepted for publication in MNRAS titled: "About AGN ionization echoes, thermal echoes, and ionization deficits in low redshift Lyman-alpha blobs". [10] GBGs are thought to be low redshift examples of 'Lyman alpha blobs' (LABs). [10]

The abstract states: "We report the discovery of 14 Lyman-alpha blobs (LABs) at z~0.3, existing at least 4-7 billion years later in the Universe than all other LABs known." Further on: "Because of their proximity and high flux densities, GBs are perfect targets to study AGN feedback, mode switching and the Ly-alpha escape." [10]

See also

Related Research Articles

<span class="mw-page-title-main">Quasar</span> Active galactic nucleus containing a supermassive black hole

A quasar is an extremely luminous active galactic nucleus (AGN). It is sometimes known as a quasi-stellar object, abbreviated QSO. The emission from an AGN is powered by a supermassive black hole with a mass ranging from millions to tens of billions of solar masses, surrounded by a gaseous accretion disc. Gas in the disc falling towards the black hole heats up and releases energy in the form of electromagnetic radiation. The radiant energy of quasars is enormous; the most powerful quasars have luminosities thousands of times greater than that of a galaxy such as the Milky Way. Quasars are usually categorized as a subclass of the more general category of AGN. The redshifts of quasars are of cosmological origin.

An active galactic nucleus (AGN) is a compact region at the center of a galaxy that emits a significant amount of energy across the electromagnetic spectrum, with characteristics indicating that this luminosity is not produced by the stars. Such excess, non-stellar emissions have been observed in the radio, microwave, infrared, optical, ultra-violet, X-ray and gamma ray wavebands. A galaxy hosting an AGN is called an active galaxy. The non-stellar radiation from an AGN is theorized to result from the accretion of matter by a supermassive black hole at the center of its host galaxy.

<span class="mw-page-title-main">Reionization</span> Process that caused matter to reionize early in the history of the Universe

In the fields of Big Bang theory and cosmology, reionization is the process that caused electrically neutral atoms in the universe to reionize after the lapse of the "dark ages".

<span class="mw-page-title-main">Lyman-alpha blob</span> Astronomical object type

In astronomy, a Lyman-alpha blob (LAB) is a huge concentration of a gas emitting the Lyman-alpha emission line. LABs are some of the largest known individual objects in the Universe. Some of these gaseous structures are more than 400,000 light years across. So far they have only been found in the high-redshift universe because of the ultraviolet nature of the Lyman-alpha emission line. Since Earth's atmosphere is very effective at filtering out UV photons, the Lyman-alpha photons must be redshifted in order to be transmitted through the atmosphere.

<span class="mw-page-title-main">Low-ionization nuclear emission-line region</span> Type of galactic nucleus

A low-ionization nuclear emission-line region (LINER) is a type of galactic nucleus that is defined by its spectral line emission. The spectra typically include line emission from weakly ionized or neutral atoms, such as O, O+, N+, and S+. Conversely, the spectral line emission from strongly ionized atoms, such as O++, Ne++, and He+, is relatively weak. The class of galactic nuclei was first identified by Timothy Heckman in the third of a series of papers on the spectra of galactic nuclei that were published in 1980.

<span class="mw-page-title-main">Light echo</span> Astronomical phenomenon caused by light reflected off surfaces distant from the source

A light echo is a physical phenomenon caused by light reflected off surfaces distant from the source, and arriving at the observer with a delay relative to this distance. The phenomenon is analogous to an echo of sound, but due to the much faster speed of light, it mostly manifests itself only over astronomical distances.

<span class="mw-page-title-main">Galaxy Zoo</span> Crowdsourced astronomy project

Galaxy Zoo is a crowdsourced astronomy project which invites people to assist in the morphological classification of large numbers of galaxies. It is an example of citizen science as it enlists the help of members of the public to help in scientific research.

<span class="mw-page-title-main">Hanny's Voorwerp</span> Astronomical object appearing as a bright blob, discovered by Hanny van Arkel

Hanny's Voorwerp is a type of astronomical object called a quasar ionization echo. It was discovered in 2007 by Dutch schoolteacher Hanny van Arkel while she was participating as a volunteer in the Galaxy Zoo project, part of the Zooniverse group of citizen science websites. Photographically, it appears as a bright blob close to spiral galaxy IC 2497 in the constellation Leo Minor.

<span class="mw-page-title-main">Pea galaxy</span> Possible type of luminous blue compact galaxy

A Pea galaxy, also referred to as a Pea or Green Pea, might be a type of luminous blue compact galaxy that is undergoing very high rates of star formation. Pea galaxies are so-named because of their small size and greenish appearance in the images taken by the Sloan Digital Sky Survey (SDSS).

<span class="mw-page-title-main">9io9</span> Galaxy in the constellation Cetus

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The photon underproduction crisis is a cosmological discussion concerning the purported deficit between observed photons and predicted photons.

<span class="mw-page-title-main">Tololo 1247-232</span> Galaxy in the constellation Hydra

Tololo 1247-232 is a small galaxy at a distance of 652 million light-years. It is situated in the southern equatorial constellation of Hydra. Visually, Tol 1247 appears to be an irregular or possibly a barred spiral galaxy. Tol 1247 is named after the surveys that were carried at the Cerro Tololo Inter-American Observatory (CTIO), the first of which was in 1976. It is one of nine galaxies in the local universe known to emit Lyman continuum photons.

<span class="mw-page-title-main">A1703 zD6</span>

A1703 zD6 is a strongly lensed Lyman-alpha emitter. It is located behind a foreground galaxy cluster known as Abell 1703, hence its name. It has a spectroscopically determined redshift of over 7, corresponding to a light travel time of 12.9 billion years. It is located in the Canes Venatici constellation. It was discovered in 2012, by a group led by L. D. Bradley, published in The Astrophysical Journal.

<span class="mw-page-title-main">TON 618</span> Quasar and Lyman-alpha blob in the constellation Canes Venatici

TON 618 is a hyperluminous, broad-absorption-line, radio-loud quasar, and Lyman-alpha blob located near the border of the constellations Canes Venatici and Coma Berenices, with the projected comoving distance of approximately 18.2 billion light-years from Earth. It possesses one of the most massive black holes ever found, at 40.7 billion M☉.

<span class="mw-page-title-main">Teacup galaxy</span> Low redshift quasar in the constellation Boötes

The Teacup galaxy, also known as the Teacup AGN or SDSS J1430+1339 is a low redshift type 2 quasar, showing an extended loop of ionized gas resembling a handle of a teacup, which was discovered by volunteers of the Galaxy Zoo project and labeled as a Voorwerpje.

<span class="mw-page-title-main">Extended emission-line region</span> Interstellar clouds

An extended emission-line region (EELR) is a giant interstellar cloud ionized by the radiation of an active galactic nucleus (AGN) inside a galaxy or photons produced by the shocks associated with the radio jets. An EELR can appear as a resolved cloud in relative nearby galaxies and as narrow emission lines in more distant galaxies.

<span class="mw-page-title-main">IRAS 09104+4109</span> Galaxy in the constellation Lynx

IRAS 09104+4109 is a galaxy located in the constellation Lynx. With a redshift of 0.440797, the light travel time for this galaxy, corresponds to 4.8 billion light-years from Earth. It is the brightest cluster galaxy in MACS J0913.7+4056 galaxy cluster and classified as a hyperluminous infrared galaxy.

<span class="mw-page-title-main">Markarian 463</span> Galaxy in the constellation of Boötes

Markarian 463 known as UGC 8850, is a galaxy merger located in the constellation Boötes. It is located 706 million light years from Earth. It is classified a double nucleus Seyfert galaxy.

<span class="mw-page-title-main">J1000+1242</span> Type 2 quasar located in the constellation Leo

J1000+1242 known as SDSS J1000+1242 or J1000+12 is a radio-quiet type-2 quasar, located in the constellation Leo. It is located 2 billion light years from Earth and is classified as a Seyfert galaxy.

References

  1. 1 2 3 4 5 6 7 8 9 10 11 M. Schirmer; R. Diaz; K.Holhjem; N.A. Levenson; C. Winge (2013). "A Sample of Seyfert-2 Galaxies with Ultraluminous Galaxy-wide Narrow-line Regions: Quasar Light Echoes?". The Astrophysical Journal. 763 (1): 19. arXiv: 1211.7098 . Bibcode:2013ApJ...763...60S. doi:10.1088/0004-637X/763/1/60. S2CID   53386055.
  2. ↑ "Galaxy-wide Echoes from the Past". 2012-12-05. Retrieved 2014-05-31.
  3. ↑ ""Green-bean Galaxies" and the Demise of Quasars". 2012-12-05. Retrieved 2014-06-12.
  4. ↑ "Galaxy-wide Echoes from the past". 2012-12-05. Retrieved 2014-06-12.
  5. ↑ C. Cardamone; K. Schawinski; M. Sarzi; S.P. Bamford; N. Bennert; C.M. Urry; C. Lintott; W.C. Keel; J. Parejko; R.C. Nichol; D. Thomas; D. Andreescu; P. Murray; M.J. Raddick; A. Slosar; A. Szalay; J. Vandenberg (2009). "Galaxy Zoo Green Peas: Discovery of A Class of Compact Extremely Star-Forming Galaxies". Monthly Notices of the Royal Astronomical Society . 399 (3): 1191–1205. arXiv: 0907.4155 . Bibcode:2009MNRAS.399.1191C. doi: 10.1111/j.1365-2966.2009.15383.x . S2CID   14663963.
  6. ↑ C.J Lintott; K. Schawinski; W. Keel; H. van Arkel; N. Bennert; E. Edmondson; D. Thomas; D.J.B. Smith; P.D. Herbert; M.J. Jarvis; S. Virani; D. Andreescu; S.P. Bamford; K. Land; P. Murray; R.C. Nichol; M.J. Raddick; A. Slosar; A. Szalay; J. Vandenberg (2009). "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 . S2CID   16752721.
  7. 1 2 W.C. Keel; S.D. Chojnowski; V.N. Bennert; K. Schawinski; C.J. Lintott; S. Lynn; A. Pancoast; C. Harris; A.M. Nierenberg; A. Sonnenfeld; R. Proctor (February 2012). "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 . S2CID   13989196.
  8. ↑ A.C. Fabian (2012). "Observational Evidence of Active Galactic Nuclei Feedback". Annual Review of Astronomy and Astrophysics . 50: 455–489. arXiv: 1204.4114 . Bibcode:2012ARA&A..50..455F. doi:10.1146/annurev-astro-081811-125521.
  9. 1 2 R.L. Davies; M. Schirmer; J.E.H. Turner (May 2015). "The "Green Bean" Galaxy SDSS J224024.1--092748: Unravelling the emission signature of a quasar ionization echo". MNRAS. 449 (2): 1731–1752. arXiv: 1502.07754 . Bibcode:2015MNRAS.449.1731D. doi: 10.1093/mnras/stv343 .
  10. 1 2 3 M. Schirmer; S. Malhotra; N.A. Levenson; Fu H.; R.L. Davies; W.C. Keel; P. Torrey; V.N. Bennert; A. Pancoast; J.E.H. Turner (2016). "About AGN ionization echoes, thermal echoes, and ionization deficits in low redshift Lyman-alpha blobs". Monthly Notices of the Royal Astronomical Society. 463 (2): 1554–1586. arXiv: 1607.06481 . Bibcode:2016MNRAS.463.1554S. doi: 10.1093/mnras/stw1819 .
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