3C 285

{{Short description|Galaxy in constellation Canes Venatici}}

{{Infobox galaxy

| name = 3C 285

| image = 3C 285 NVAS 1.52I4.09 AV0127 1986AUG29 1 96.7U5.73M.jpg

| caption = 3C 285 in radiowaves

| epoch = J2000

| ra = {{RA|13|21|17.813}}{{cite web |url=http://simbad.u-strasbg.fr/simbad/sim-id?Ident=3C+285 |title=Query : 3C 285 |website=Simbad |publisher=Centre de Données astronomiques de Strasbourg |access-date=2 June 2015}}

| dec = {{DEC|+42|35|15.38}}

| constellation name = Canes Venatici

| z = 0.0794{{cite web

|website=NASA/IPAC Extragalactic Database

|title=NED results for object 3C 285

|url=http://nedwww.ipac.caltech.edu/cgi-bin/nph-objsearch?objname=3C+285&extend=no

|access-date=2 June 2015 }}

| type = rG, Rad, AGN, G, GiG, QSO
G, FR II

| h_radial_v = 23,799 ± 5 km/s

| dist_ly = {{convert|323|Mpc|ly|lk=on}} {{hub|0.73|link=yes}}

| appmag_v = 16.23

| size_v = 0.417' x 0.242'

| notes =

| names = DA 343, LEDA 46625, 3C 285, 4C +42.37, 2MASX J13211781+4235153

}}

3C 285 is a radio galaxy located in the constellation Canes Venatici. It is located about 1 billion light years away. It is a Fanaroff-Riley 2 radio galaxy and is hosted in a disturbed spiral galaxy.{{cite journal |last1=Hardcastle |first1=M. J. |last2=Kraft |first2=R. P. |last3=Worrall |first3=D. M. |last4=Croston |first4=J. H. |last5=Evans |first5=D. A. |last6=Birkinshaw |first6=M. |last7=Murray |first7=S. S. |title=The Interaction between Radio Lobes and Hot Gas in the Nearby Radio Galaxies 3C 285 and 3C 442A |journal=The Astrophysical Journal |date=10 June 2007 |volume=662 |issue=1 |pages=166–181 |doi=10.1086/517997|arxiv=astro-ph/0703080 |bibcode=2007ApJ...662..166H }}

3C 285 is the brightest member of a small galaxy group. Its morphology is peculiar, with an S-shaped envelope that points to another galaxy of the group, located to the northwest. A gas filament 26 arcseconds long extends towards that galaxy.{{cite journal |last1=Baum |first1=Stefi Alison |last2=Heckman |first2=Timothy M. |last3=Bridle |first3=Alan |last4=van Breugel |first4=Wil J. M. |last5=Miley |first5=George K. |title=Extended optical-line-emitting gas in radio galaxies - Broad-band optical, narrow-band optical, and radio imaging of a representative sample |journal=The Astrophysical Journal Supplement Series |date=December 1988 |volume=68 |pages=643 |doi=10.1086/191301|doi-access=free |bibcode=1988ApJS...68..643B }} In optical and ultraviolet observations the galaxy features dust lanes, two across the galaxy and one perpendicular to them that also obscures part of the nucleus. Along the edges of the dust lanes knots of elevated ultraviolet emission indicate locations of where new stars are formed.{{cite journal |last1=Allen |first1=Mark G. |last2=Sparks |first2=William B. |last3=Koekemoer |first3=Anton |last4=Martel |first4=Andre R. |last5=O’Dea |first5=Christopher P. |last6=Baum |first6=Stefi A. |last7=Chiaberge |first7=Marco |last8=Macchetto |first8=F. Duccio |last9=Miley |first9=George K. |title=Ultraviolet Hubble Space Telescope Snapshot Survey of 3CR Radio Source Counterparts at Low Redshift |journal=The Astrophysical Journal Supplement Series |date=April 2002 |volume=139 |issue=2 |pages=411–438 |doi=10.1086/338823|doi-access=free |arxiv=astro-ph/0112208 |bibcode=2002ApJS..139..411A }} In the centre of 3C 285 lies a supermassive black hole whose mass is estimated to be 10^7.70±0.10 (40-63 million) {{solar mass|link=yes}} based on stellar velocity dispersion.{{cite journal |last1=Mezcua |first1=M.|author1-link=Mar Mezcua |last2=Lobanov |first2=A. P. |last3=Chavushyan |first3=V. H. |last4=León-Tavares |first4=J. |title=Black hole masses and starbursts in X-shaped radio sources |journal=Astronomy & Astrophysics |date=March 2011 |volume=527 |pages=A38 |doi=10.1051/0004-6361/201015535|arxiv=1008.0977 |bibcode=2011A&A...527A..38M }}

When observed in radiowaves, 3C 285 has two lobes with filamentary structures in them, and a jet is visible in the eastern lobe. A blue star forming region, named 3C 285/09.6, has been detected within the eastern radio lobe, and it has been suggested that the star formation was induced by the compression of a region of dense intergalactic gas by the radio jet.{{cite journal |last1=van Breugel |first1=Wil J. M. |last2=Dey |first2=Arjun |title=Induced star formation in a radio lobe of 3C 285? |journal=The Astrophysical Journal |date=September 1993 |volume=414 |pages=563 |doi=10.1086/173103|bibcode=1993ApJ...414..563V }} The gas mass of the region is estimated to be less than {{val|6.2|e=8|ul=M_solar}} based on CO imaging and so it is estimated to be depleted if star formation continues at the current rate in less than a billion years.{{cite journal |last1=Salomé |first1=Q. |last2=Salomé |first2=P. |last3=Combes |first3=F. |title=Jet-induced star formation in 3C 285 and Minkowski's Object |journal=Astronomy & Astrophysics |date=February 2015 |volume=574 |pages=A34 |doi=10.1051/0004-6361/201424932|arxiv=1410.8367 |bibcode=2015A&A...574A..34S }}