NGC 1266 explained

NGC 1266
Epoch:J2000
Ra:[1]
Type:S0[2]
Dist Ly:29.9 Mpc
Z:0.007238 ± 0.000017
Half Light Radius Arcminsec:20.4"
Half Light Radius Pc:2.96 kpc
H Radial V:2170 ± 5 km s−1
Constellation Name:Eridanus
Notes:AGN, molecular outflow, suppressed SFR
Names:PGC 12131

NGC 1266 is a lenticular galaxy in the constellation Eridanus. Although not currently starbursting, it has undergone a period of intense star formation in the recent past, ceasing only ≈500 Myr ago.[3] The galaxy is host to an obscured active galactic nucleus.[4]

A massive molecular outflow, with 2.4 × 107 M

\odot

of hydrogen, is present from the nucleus of the galaxy,[4] at a rate of 110 M

\odot

 yr−1.[5] Less than 2% of the gas (2 M

\odot

 yr−1) is escaping the galaxy. Momentum coupling to the jet of the AGN is likely driving the outflow.[5]

The current observed star-formation rate (SFR) of ~0.87 M

\odot

 yr−1 is significantly lower than expected for a galaxy of its properties, suppressed by a factor of 50 to 150. Authors have put forth several hypotheses to explain these observations. The most likely scenario is that the AGN-driven molecular outflow is injecting turbulence into the nuclear regions, preventing gravitational collapse of molecular clouds.[5] NGC 1266 is the first known intermediate-mass galaxy to show AGN-driven suppression of star formation.

Two hypotheses exist to explain NGC 1266's nuclear activity and excessive far-IR emission. Either a heavily obscured ultracompact starburst is present in the nuclear regions, or a powerful buried AGN is present, beyond what has been inferred from other observations. Neither scenario is without problems. The black hole at the center of the galaxy is likely growing according to the M–sigma relation, and eventually the outflow will result in the removal of the majority of the gas from the nucleus.[5]

Notes and References

  1. 2003A&A...412...45P . HYPERLEDA. I. Identification and designation of galaxies . Astronomy and Astrophysics . 412 . 45–55 . Paturel . G. . Petit . C. . Prugniel . Ph. . Theureau . G. . Rousseau . J. . Brouty . M. . Dubois . P. . Cambrésy . L. . 2003 . 10.1051/0004-6361:20031411 . free .
  2. 2011MNRAS.413..813C . 10.1111/j.1365-2966.2010.18174.x . 1012.1551. The ATLAS3D project - I. A volume-limited sample of 260 nearby early-type galaxies: Science goals and selection criteria . Monthly Notices of the Royal Astronomical Society . 413 . 2 . 813–836 . 2011 . Cappellari . Michele . Emsellem . Eric . Krajnović . Davor . McDermid . Richard M . Scott . Nicholas . Verdoes Kleijn . G. A . Young . Lisa M . Alatalo . Katherine . Bacon . R . Blitz . Leo . Bois . Maxime . Bournaud . Frédéric . Bureau . M . Davies . Roger L . Davis . Timothy A . De Zeeuw . P. T . Duc . Pierre-Alain . Khochfar . Sadegh . Kuntschner . Harald . Lablanche . Pierre-Yves . Morganti . Raffaella . Naab . Thorsten . Oosterloo . Tom . Sarzi . Marc . Serra . Paolo . Weijmans . Anne-Marie . 15391206 . 9 .
  3. 2014ApJ...780..186A . 10.1088/0004-637X/780/2/186 . 1311.6469. Ngc 1266 As a Local Candidate for Rapid Cessation of Star Formation . The Astrophysical Journal . 780 . 2 . 186 . 2013 . Alatalo . Katherine . Nyland . Kristina . Graves . Genevieve . Deustua . Susana . Griffin . Kristen Shapiro . Duc . Pierre-Alain . Cappellari . Michele . McDermid . Richard M . Davis . Timothy A . Crocker . Alison F . Young . Lisa M . Chang . Philip . Scott . Nicholas . Cales . Sabrina L . Bayet . Estelle . Blitz . Leo . Bois . Maxime . Bournaud . Frédéric . Bureau . Martin . Davies . Roger L . De Zeeuw . P. T . Emsellem . Eric . Khochfar . Sadegh . Krajnović . Davor . Kuntschner . Harald . Morganti . Raffaella . Naab . Thorsten . Oosterloo . Tom . Sarzi . Marc . Serra . Paolo . 14612978 . 9 .
  4. 2011ApJ...735...88A . 10.1088/0004-637X/735/2/88 . 1104.2326. Discovery of an Active Galactic Nucleus Driven Molecular Outflow in the Local Early-Type Galaxy Ngc 1266 . The Astrophysical Journal . 735 . 2 . 88 . 2011 . Alatalo . K . Blitz . L . Davis . T. A . Bureau . M . Lopez . L. A . Cappellari . M . Scott . N . Shapiro . K. L . Crocker . A. F . Martín . S . Bois . M . Bournaud . F . Davies . R. L . De Zeeuw . P. T . Duc . P.-A . Emsellem . E . Falcón-Barroso . J . Khochfar . S . Krajnović . D . Kuntschner . H . Lablanche . P.-Y . McDermid . R. M . Morganti . R . Naab . T . Oosterloo . T . Sarzi . M . Serra . P . Weijmans . A . 19036583 . 9 .
  5. 2015ApJ...798...31A . 10.1088/0004-637X/798/1/31 . 1410.4556. Suppression of Star Formation in Ngc 1266 . The Astrophysical Journal . 798 . 1 . 31 . 2014 . Alatalo . Katherine . Lacy . Mark . Lanz . Lauranne . Bitsakis . Theodoros . Appleton . Philip N . Nyland . Kristina . Cales . Sabrina L . Chang . Philip . Davis . Timothy A . De Zeeuw . P. T . Lonsdale . Carol J . Martín . Sergio . Meier . David S . Ogle . Patrick M . 15747241 . 9 .