Circinus Galaxy

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

{{Infobox Galaxy

| image = File:142_circinus_galaxy.png

| image_size = 300px

| caption = A Hubble Space Telescope (HST) image of the core of the Circinus Galaxy.

| name = Circinus Galaxy

| type = SA(s)b

| constellation name = Circinus

| epoch = J2000

| z = 426 ± 25 km/s

| ra = {{RA|14|13|9.9}}

| dec = {{DEC|-65|20|21}}

| dist_pc = {{convert|3.14|+/-|0.22|Mpc|Mly|sigfig=3|abbr=on|lk=on}}{{hub|0.6774}}

| dist_ly =

| appmag_v = 12.1

| mass =

| size = {{cvt|14.85|x|6.09|kpc|ly|sigfig=4|abbr=on|lk=on|disp=x|
(|)}}
{{small|(diameter; 2MASS K-band total isophote)}}{{cite web |url=https://ned.ipac.caltech.edu/cgi-bin/objsearch?objname=ESO+97-G13&extend=no&hconst=67.74&omegam=0.3089&omegav=0.6911&corr_z=1&out_csys=Equatorial&out_equinox=J2000.0&obj_sort=RA+or+Longitude&of=pre_text&zv_breaker=30000.0&list_limit=5&img_stamp=YES |title=Detailed Information for Object ESO 97-G13 |work=NASA/IPAC Extragalactic Database |access-date=September 13, 2023}}{{efn|name=Scale|The quoted diameters in this infobox was based on NED's provided scale of 15 pc/arcsec multiplied with the given angular diameters.}}
{{cvt|10.38|x|5.19|kpc|ly|sigfig=5|abbr=on|lk=on|disp=x|
(|)}}
{{small|(diameter; ESO 90% total B-band)}}{{efn|name=Scale}}

| size_v = {{val|6.9|x|3.0|ul=arcminute}}

| notes =

| names = ESO 97-G13, LEDA 50779

}}

The Circinus Galaxy (ESO 97-G13) is a Seyfert galaxy{{cite simbad

| title=NAME Circinus Galaxy

| access-date=2007-04-20}} in the constellation of Circinus. It is located 4 degrees below the Galactic plane, and, at a distance of {{convert|4.0|Mpc|Mly|lk=on|abbr=on}}, is one of the closest major galaxies to the Milky Way.{{cite journal

|author1=Maiolino, R.

|author2=Krabbe, A.

|author3=Thatte, N.

|author4=Genzel, R.

|year=1998

|title=Seyfert Activity and Nuclear Star Formation in the Circinus Galaxy

|journal=The Astrophysical Journal

|volume=493

|issue=2

|pages=650–65

|arxiv = astro-ph/9709091

|bibcode = 1998ApJ...493..650M

|doi = 10.1086/305150 |s2cid=16365899

}} The galaxy is undergoing tumultuous changes, as rings of gas are likely being ejected from the galaxy.{{Cite journal |last1=Izumi |first1=Takuma |last2=Wada |first2=Keiichi |last3=Imanishi |first3=Masatoshi |last4=Nakanishi |first4=Kouichiro |last5=Kohno |first5=Kotaro |last6=Kudoh |first6=Yuki |last7=Kawamuro |first7=Taiki |last8=Baba |first8=Shunsuke |last9=Matsumoto |first9=Naoki |last10=Fujita |first10=Yutaka |last11=Tristram |first11=Konrad R. W. |date=2023-11-03 |title=Supermassive black hole feeding and feedback observed on subparsec scales |url=https://www.science.org/doi/10.1126/science.adf0569 |journal=Science |language=en |volume=382 |issue=6670 |pages=554–559 |doi=10.1126/science.adf0569 |pmid=37917712 |issn=0036-8075|arxiv=2305.03993 |bibcode=2023Sci...382..554I }} Its outermost ring is 1400 light-years across while the inner ring is 260 light-years across.{{citation needed|date=March 2018}} Although the Circinus galaxy can be seen using a small telescope, it was not noticed until 1977{{cite book

|last=Inglis

|first=Mike

|title=Astronomy of the Milky Way: Observer's Guide to the Southern Sky

|publisher=Springer

|location=New York, New York

|year=2004

|page=103

|isbn=978-1-85233-742-1

|url=https://books.google.com/books?id=1r0qvMjSCGAC&pg=SA3-PA103}} because it lies close to the plane of the Milky Way and is obscured by galactic dust. The Circinus Galaxy is a Type II Seyfert galaxy and is one of the closest known active galaxies to the Milky Way, though it is probably slightly farther away than Centaurus A.

Circinus Galaxy produced supernova SN 1996cr, which was identified over a decade after it exploded. This supernova event was first observed during 2001 as a bright, variable object in a Chandra X-ray Observatory image, but it was not confirmed as a supernova until years later.

The Circinus Galaxy is one of twelve large galaxies in the "Council of Giants" surrounding the Local Group in the Local Sheet. {{cite journal

|title=A Council of Giants

|first=Marshall L.

|last=McCall

|date=29 April 2013

|journal=Monthly Notices of the Royal Astronomical Society

|volume=440

|issue=1

|pages=405–426

|publication-date=10 March 2014

|doi=10.1093/mnras/stu199

|doi-access=free

|arxiv=1403.3667

|bibcode=2014MNRAS.440..405M}} One object is possibly a satellite of the Circinus Galaxy, known as HIZOA J1353-58. HIZOA J1353-58 was discovered in a survey of neutral hydrogen (H I) and is located within the Zone of Avoidance.{{cite journal|doi=10.3847/0004-6256/151/3/52|title=The Parkes H I Zone of Avoidance Survey|year=2016|last1=Staveley-Smith|first1=L.|last2=Kraan-Korteweg|first2=R. C.|last3=Schröder|first3=A. C.|last4=Henning|first4=P. A.|last5=Koribalski|first5=B. S.|last6=Stewart|first6=I. M.|last7=Heald|first7=G.|journal=The Astronomical Journal|volume=151|issue=3|page=52|arxiv=1602.02922|bibcode=2016AJ....151...52S|s2cid=54665552 |doi-access=free }}

NuSTAR detected a ULX at the edge of this galaxy, a black hole about 100 times the mass of the Sun. {{cite web | url=https://www.jpl.nasa.gov/images/pia17560-black-holes-of-the-circinus-galaxy | title=Black Holes of the Circinus Galaxy | website=Jet Propulsion Laboratory }}{{cite web | url=https://www.nasa.gov/image-article/black-holes-of-circinus-galaxy/ | title=Black Holes of the Circinus Galaxy - NASA }}