NGC 7793

{{Infobox galaxy

| name = {{PAGENAME}}

| image = File:Jets and explosions in NGC 7793 (15301077796).jpg

| caption = Hubble Space Telescope image of the small bulge and spiral arms of NGC 7793

| alt =

| epoch = J2000

| pronounce =

| constellation name = Sculptor

| ra = {{RA|23|57|49.753}}

| dec = {{DEC|−32|35|27.71}}

| z = 0.000749{{r|ned}}

| h_radial_v = {{val|227|fmt=commas|u=km/s}}

| gal_v =

| dist_pc =

| dist_ly = {{cvt|3.7325|Mpc|Mly|1|adj=ri1|order=flip|lk=on}}

| group_cluster = Sculptor Group

| type = SA(s)d

| mass = Stellar: {{Val|3.2|e=9}}

| mass_light_ratio =

| size = ~{{convert|15.61|kpc|ly|abbr=on|lk=on|order=flip}} (estimated){{r|ned}}

| stars =

| appmag_v = 10.0

| appmag_b =

| absmag_v =

| size_v = {{Val|9.3|×|6.3|u=arcminute}}

| half_light_radius_pc =

| half_light_radius_arcminsec =

| h1_scale_length_pc =

| h1_scale_length_arcminsec =

| xray_radius_pc =

| xray_radius_arcminsec =

| notes =

| names = {{odlist | IRAS= 23552-3252 | PGC=73049 | name= ESO 349- G 012 | MCG= -06-01-009}}

| references =

}}

NGC 7793 is a flocculent spiral galaxy in the southern constellation of Sculptor. It was discovered on July 14, 1826, by Scottish astronomer James Dunlop.{{cite web | url = https://cseligman.com/text/atlas/ngc77a.htm#7793 | title = New General Catalogue Objects: NGC{{nbsp}}7793 | last = Seligman | first = Courtney | website = Celestial Atlas | access-date = 25 April 2025 }} The galaxy is located at a distance of {{cvt|3.7325|Mpc|Mly|1|disp=output number only}} million light years and is receding with a heliocentric radial velocity of {{val|227|fmt=commas|u=km/s}}. NGC 7793 is one of the five brightest galaxies within the Sculptor Group.

The morphological class of NGC 7793 is SA(s)d, indicating it is unbarred spiral galaxy (SA) with no inner ring structure (s) and the arms are loosely wound and disorganized (d). It is flocculent in appearance with a very small bulge and a star cluster at the nucleus. The galactic disk is inclined at an angle of 53.7° to the line of sight from the Earth. The visible profile is elliptical in form with an angular size of {{Val|9.3|×|6.3|u=arcminute}} and a major axis aligned along a position angle of 99.3°. There are two nearby dwarf galaxy companions.

NGC 7793 hosts the ultra-luminous X-ray pulsar (ULXP) referred to as NGC 7793 P13 (previously believed to harbor a black hole), which consists of a 0.42-second pulsar in a 64-day orbit with a 18–23 solar mass B9Ia companion star.

Supernova

One supernova has been observed in NGC 7793. SN 2008bk (type II-P, mag. 12.6) was discovered by Berto Monard (bio-it) on March 25, 2008.{{cite journal|bibcode=2008CBET.1315....1M |title=Supernova 2008bk in NGC 7793 |last1=Monard |first1=L. A. G. |journal=Central Bureau Electronic Telegrams |date=2008 |issue=1315 |page=1 | url=http://www.cbat.eps.harvard.edu/cbet/001300/CBET001315.txt}}{{cite web | website=Transient Name Server | title=SN{{nbsp}}2008bk | url=https://www.wis-tns.org/object/2008bk | publisher = IAU | access-date=25 April 2025}} It reached apparent magnitude 12.5, making it the second-brightest supernova of 2008. The progenitor of this supernova was a red supergiant, observed only 547 days prior to the explosion.{{cite journal | bibcode=2008ApJ...688L..91M |title=VLT Detection of a Red Supergiant Progenitor of the Type II-P Supernova 2008bk | last1=Mattila | first1=S. | last2=Smartt | first2=S. J. | last3=Eldridge | first3=J. J. | last4=Maund | first4=J. R. | last5=Crockett | first5=R. M. | last6=Danziger | first6=I. J. | journal=The Astrophysical Journal | date=2008 | volume=688 | issue=2 | pages=L91–L94 | doi=10.1086/595587 | arxiv=0809.0206 | doi-access=free}}

Gallery

Phot-14b-09-fullres 2.JPG|Visual and infrared image of NGC 7793

SN2008bk.jpg|SN 2008bk before it exploded (left) and after the explosion (right)

References

{{reflist|refs=

{{cite journal | title=Tracing Young Star-forming Clumps in the Nearby Flocculent Spiral Galaxy NGC 7793 with UVIT Imaging | last1=Mondal | first1=Chayan | last2=Subramaniam | first2=Annapurni | last3=George | first3=Koshy | last4=Postma | first4=Joseph E. | last5=Subramanian | first5=Smitha | last6=Barway | first6=Sudhanshu | display-authors=1 | journal=The Astrophysical Journal | volume=909 | issue=2 | id=203 | pages=13 | date=March 2021 | doi=10.3847/1538-4357/abe0b4 | arxiv=2101.11314 | bibcode=2021ApJ...909..203M | s2cid=231718940 | doi-access=free}}

{{cite book | title=The Cambridge Photographic Atlas of Galaxies | first1=Michael | last1=König | first2=Stefan | last2=Binnewies | isbn=9781108103091 | date=2017 | page=68 | publisher=Cambridge University Press | url=https://books.google.com/books?id=OEszDwAAQBAJ&pg=PA68}}

{{cite journal | title=Dust properties and star formation of approximately a thousand local galaxies | display-authors=1 | last1=Lianou | first1=S. | last2=Barmby | first2=P. | last3=Mosenkov | first3=A. A. | last4=Lehnert | first4=M. | last5=Karczewski | first5=O. | journal=Astronomy & Astrophysics | volume=631 | id=A38 | pages=19 | date=November 2019 | doi=10.1051/0004-6361/201834553 | arxiv=1906.02712 | bibcode=2019A&A...631A..38L | s2cid=174801441}}

{{cite journal | title=Cosmicflows-3 | display-authors=1 | last1=Tully | first1=R. Brent | last2=Courtois | first2=Hélène M. | last3=Sorce | first3=Jenny G. | journal=The Astronomical Journal | date=August 3, 2016 |volume=152 | issue=2 | pages=50 | doi=10.3847/0004-6256/152/2/50 | arxiv=1605.01765 | bibcode=2016AJ....152...50T | s2cid=250737862 | doi-access=free}}

{{cite web

| website = NASA/IPAC Extragalactic Database

| title = Results for object NGC 7793

| url = https://ned.ipac.caltech.edu/byname?objname=NGC+7793

| access-date = 2006-11-21}}

{{cite journal | title=A Catalogue of Nebulae and Clusters of Stars in the Southern Hemisphere observed in New South Wales | first=Dunlop | last=James | journal=Philosophical Transactions of the Royal Society | volume=118 | pages = 113–151 | date = 1828 | bibcode=1828RSPT..118..113D | jstor=107841 | doi = 10.1098/rstl.1828.0010 | url=https://zenodo.org/record/1432362 | doi-access = free}}

{{cite journal | author=I. D. Karachentsev | display-authors=4 | author2=E. K. Grebel | author3=M. E. Sharina | author4=A. E. Dolphin | author5=D. Geisler | author6=P. Guhathakrta | author7=P. W. Hodge | author8=V. E. Karachentseva | author9=A. Sarajedini | author10=P. Seitzer | title=Distances to nearby galaxies in Sculptor | journal=Astronomy and Astrophysics | date=2003 | volume=404 | issue=1 | pages=93–111 | bibcode=2003A&A...404...93K | doi=10.1051/0004-6361:20030170|arxiv = astro-ph/0302045 | s2cid=54977869}}

{{cite web |title = Supernova 2008bk in NGC 7793 | website = Rochester Astronomy |author = David Bishop |url = https://www.rochesterastronomy.org/sn2008/sn2008bk.html |access-date = 2025-04-25 }}

{{cite web |title = Bright Supernovae – 2008 | website = Rochester Astronomy |author = David Bishop |url = https://www.rochesterastronomy.org/sn2008/index.html |access-date = 2025-04-25}}

{{cite journal | title=Discovery of a 0.42-s pulsar in the ultraluminous X-ray source NGC 7793 P13 | last=Israel | first=G.L. | journal=Monthly Notices of the Royal Astronomical Society: Letters | date=September 2016 | volume=466 | pages=L48–L52 | doi=10.1093/mnrasl/slw218 | doi-access=free | arxiv=1609.06538}}

}}