NGC 545

{{Short description|Galaxy in the constellation Cetus}}

{{Infobox galaxy

| name = NGC 545

| image = Hubble Space Telecope image of galaxies NGC 545 and NGC 547.webp

| caption = NGC 545 (upper left) and NGC 547 (center) imaged by the Hubble Space Telescope

| epoch = J2000

| type = SA0- {{cite web

| title=NASA/IPAC Extragalactic Database

| work=Results for NGC 545

| url=http://ned.ipac.caltech.edu/cgi-bin/nph-objsearch?objname=NGC+545

| access-date=2019-01-18 }}

| ra = {{RA|01|25|59.1}}

| dec = {{DEC|-01|20|25}}

| dist_ly = 250 ± 55 Mly (78 ± 17 Mpc)

| z = 0.017806 ± 0.000025

| h_radial_v = 5,338 ± 7 km/s

| appmag_v = 12.3

| size_v = 2.4{{prime}} × 1.6{{prime}}

| constellation name = Cetus

| group_cluster = Abell 194

| notes =

| names = UGC 1007, Arp 308, CGCG 385-132, MCG +00-04-142, PGC 5323

}}

NGC 545 is a lenticular galaxy located in the constellation Cetus. It is located at a distance of about 250 million light years from Earth, which, given its apparent dimensions, means that NGC 545 is about 180,000 light years across. It was discovered by William Herschel on October 1, 1785.{{cite web |last1=Seligman |first1=Courtney |title=NGC 545 (= PGC 5323, and with NGC 547 = Arp 308) |url=https://cseligman.com/text/atlas/ngc5.htm#545 |website=Celestial Atlas |access-date=19 November 2018}} It is a member of the Abell 194 galaxy cluster and is included along with NGC 547 in the Atlas of Peculiar Galaxies.

A weak radio source with radio jets has been associated with NGC 545. The short jet crosses the much more prominent jet of NGC 547.{{cite journal |last1=Sakelliou |first1=Irini |last2=Hardcastle |first2=M. J. |last3=Jetha |first3=N. N. |title=3C 40 in Abell 194: can tail radio galaxies exist in a quiescent cluster? |journal=Monthly Notices of the Royal Astronomical Society |date=February 2008 |volume=384 |issue=1 |pages=87–93 |doi=10.1111/j.1365-2966.2007.12465.x|doi-access=free |arxiv=0709.2133|bibcode=2008MNRAS.384...87S |s2cid=16802624 }} Observations of the centre of the galaxy by Hubble Space Telescope did not reveal the presence of dust or disk features.{{cite journal |last1=Laine |first1=Seppo |last2=van der Marel |first2=Roeland P. |last3=Lauer |first3=Tod R. |last4=Postman |first4=Marc |last5=O'Dea |first5=Christopher P. |last6=Owen |first6=Frazer N. |title=Hubble Space Telescope Imaging of Brightest Cluster Galaxies |journal=The Astronomical Journal |date=February 2003 |volume=125 |issue=2 |pages=478–505 |doi=10.1086/345823|arxiv=astro-ph/0211074 |bibcode=2003AJ....125..478L |s2cid=118558349 }} In the centre of the galaxy is believed to exist a supermassive black hole whose mass is estimated to be about 600 million (10^8.79) {{solar mass|link=yes}} based on the stellar tidal disruption rate.{{cite journal |last1=Stone |first1=Nicholas C. |last2=Metzger |first2=Brian D. |title=Rates of stellar tidal disruption as probes of the supermassive black hole mass function |journal=Monthly Notices of the Royal Astronomical Society |date=1 January 2016 |volume=455 |issue=1 |pages=859–883 |doi=10.1093/mnras/stv2281|doi-access=free |arxiv=1410.7772 |bibcode=2016MNRAS.455..859S |s2cid=119308901 }}

NGC 545 forms a pair with the equally bright NGC 547, which lies 0.5 arcminutes away. They share a common envelope,Nilson, P. (1973) Uppsala General Catalogue of Galaxies, Acta Universitatis Upsalienis, Nova Regiae Societatis Upsaliensis, Series V: A Vol. 1 however, despite their close position, no tidal features like tails or bridges have been observed.{{cite journal |last1=Fasano |first1=G. |last2=Falomo |first2=R. |last3=Scarpa |first3=R. |title=Optical surface photometry of radio galaxies — I. Observations and data analysis |journal=Monthly Notices of the Royal Astronomical Society |date=September 1996 |volume=282 |issue=1 |pages=40–66 |doi=10.1093/mnras/282.1.40|bibcode=1996MNRAS.282...40F |doi-access=free }} A stellar bridge has been detected between the galaxy pair and NGC 541,{{cite journal |last1=Croft |first1=Steve |last2=van Breugel |first2=Wil |last3=de Vries |first3=Wim |last4=Dopita |first4=Mike |last5=Martin |first5=Chris |last6=Morganti |first6=Raffaella|author6-link=Raffaella Morganti |last7=Neff |first7=Susan |last8=Oosterloo |first8=Tom |last9=Schiminovich |first9=David |last10=Stanford |first10=S. A. |last11=van Gorkom |first11=Jacqueline |title=Minkowski's Object: A Starburst Triggered by a Radio Jet, Revisited |journal=The Astrophysical Journal |date=20 August 2006 |volume=647 |issue=2 |pages=1040–1055 |doi=10.1086/505526|bibcode=2006ApJ...647.1040C |arxiv=astro-ph/0604557 |s2cid=119331218 }} which lies 4.5 arcminutes to the southwest (projected distance circa 100 kpc).{{cite journal |last1=Verdoes Kleijn |first1=Gijs A. |last2=Baum |first2=Stefi A. |last3=de Zeeuw |first3=P. Tim |last4=O'Dea |first4=Chris P. |title=Hubble Space Telescope Observations of Nearby Radio-Loud Early-Type Galaxies |journal=The Astronomical Journal |date=December 1999 |volume=118 |issue=6 |pages=2592–2617 |doi=10.1086/301135|bibcode=1999AJ....118.2592V |arxiv=astro-ph/9909256 }}

Observations of the galaxy by the Chandra X-Ray Observatory revealed sharp surface brightness edges on the northeastern part of the galaxy and an extended tail in the soft band. It has been presumed that these are the result of motion of NGC 545 towards the centre of the cluster that has been identified as the location of NGC 547.{{cite journal |last1=Bogdán |first1=Ákos |last2=Kraft |first2=Ralph P. |last3=Forman |first3=William R. |last4=Jones |first4=Christine |last5=Randall |first5=Scott W. |last6=Sun |first6=Ming |last7=O'Dea |first7=Christopher P. |last8=Churazov |first8=Eugene |last9=Baum |first9=Stefi A. |title=Chandra and ROSAT Observations of A194: Detection of an X-Ray Cavity and Mapping the Dynamics of the Cluster |journal=The Astrophysical Journal |date=10 December 2011 |volume=743 |issue=1 |pages=59 |doi=10.1088/0004-637X/743/1/59|arxiv=1106.3434 |bibcode=2011ApJ...743...59B |doi-access=free }}