Malin 1

{{Short description|Spiral galaxy in the constellation Coma Berenices}}

{{Infobox galaxy

| name = Malin 1

| image = Malin 1 Legacy Survey DR10.png

| image_size = 300px

| caption = Image by the DESI Legacy Imaging Surveys, Data Release 10

| epoch = J2000.0{{cite simbad |title=2MASX J12365934+1419494 |access-date=27 October 2010}}

| constellation name = Coma Berenices{{cite web |url=http://server1.wikisky.org/starview?object_type=2&object_id=897939 |title=PGC 42102 |work=WikiSky |access-date=27 October 2010 |archive-url=https://web.archive.org/web/20190307112340/http://server1.wikisky.org/starview?object_type=2&object_id=897939 |archive-date=7 March 2019 |url-status=live}}

| ra = {{RA|12|36|59.34697}}

| dec = {{DEC|+14|19|49.1585}}

| z = {{val|0.082702|0.000013}}

| h_radial_v = {{val|24750|10|u=km/s}}

| gal_v = {{val|24707|10|u=km/s}}

| dist_pc = {{convert|373.4|+/-|26.1|Mpc|Mly|sigfig=4|abbr=on|lk=on}}{{hub|0.6774}}

| dist_ly =

| type = SB0a

| mass = ~{{10^|12}}

| mass_light_ratio =

| stars =

| appmag_v = {{val|15.809|0.009}}

| absmag_v = {{val|-22.01|0.50}}

| size = {{convert|34.11|to|36.39|kpc|ly|sigfig=5|abbr=on|lk=on|disp=x|
(|)}}
(diameter; D_25.0 B-band and 2MASS K-band total isophotes){{efn|name=Size}}

| notes = Surrounded by a H I disk

| size_v = {{val|0.25|x|0.23|ul=arcminute}}

| names = PGC 42102, LEDA 42102, VPC 1091, 2MASX J12365934+1419494, Gaia DR2 3932516418935413504

| references =

}}

Malin 1 is a giant low surface brightness (LSB) spiral galaxy. It is located {{convert|366|Mpc|e9ly|lk=on|order=flip}} away in the constellation Coma Berenices, near the North Galactic Pole. It is one of the largest known spiral galaxies, with an approximate diameter of {{convert|650000|ly|pc|lk=on}},{{cite news |url=https://www.forbes.com/sites/brucedorminey/2013/12/22/astronomers-still-puzzle-over-low-surface-brightness-galaxies/ |title=Astronomers Still Puzzle Over 'Low Surface Brightness' Galaxies |work=Forbes |first=Bruce |last=Dorminey |date=22 December 2013 |access-date=30 December 2014}}{{cite book |url=https://books.google.com/books?id=GJ-Lts1QgrkC&pg=PA3 |title=Guinness World Records 2011 |publisher=Random House |location=New York |editor-first=Craig |editor-last=Glenday |page=3 |date=2011 |isbn=978-0-440-42310-2}} thus over six times the diameter of our Milky Way. It was discovered by astronomer David Malin in 1986 and is the first LSB galaxy verified to exist.{{cite journal |title=The Ghostliest Galaxies |journal=Scientific American |first=Gregory D. |last=Bothun |volume=276 |issue=2 |pages=56–61 |date=February 1997 |bibcode=1997SciAm.276b..40B |doi=10.1038/scientificamerican0297-56 |jstor=24993608}} Its high surface brightness central spiral is {{convert|30000|ly|pc}} across, with a bulge of {{convert|10000|ly|pc}}.{{cite web |url=http://kencroswell.com/Malin1.html |title=Malin 1: A Bizarre Galaxy Gets Slightly Less So |work=KenCroswell.com |first=Ken |last=Crosswell |date=22 January 2007}} The central spiral is a SB0a type barred-spiral.

Malin 1 is peculiar in several ways: its diameter alone would make it the largest barred spiral galaxy ever to have been observed.{{cite journal |title=A Normal Stellar Disk in the Galaxy Malin 1 |journal=The Astronomical Journal |first=Aaron J. |last=Barth |volume=133 |issue=3 |pages=1085–1091 |date=March 2007 |doi=10.1086/511180 |bibcode=2007AJ....133.1085B |arxiv=astro-ph/0701018|s2cid=14631639 }}

Malin 1 was found later to be interacting with two other galaxies, Malin 1B and SDSS J123708.91+142253.2. Malin 1B is located {{convert|14000|pc|ly|order=flip}} away from the high surface brightness central spiral of Malin 1, which may be responsible for the formation of the galaxy's central bar. Meanwhile, SDSS J123708.91+142253.2 is located within the huge, faint halo of Malin 1 and might have caused the formation of the extended low surface brightness disc through tidal stripping.

Observations by Galaz et al. in April 2014 revealed a detailed view of the spiral structure of Malin 1 in optical bands. The galaxy exhibits giant and very faint spiral arms, with some segments up to {{convert|10000|pc|ly|order=flip}} in diameter. Other details, such as possible stellar streams and formation regions, are revealed as well.{{cite journal |title=Deep Optical Images of Malin 1 Reveal New Features |journal=The Astrophysical Journal Letters |first1=Gaspar |last1=Galaz |first2=Carlos |last2=Milovic |first3=Vincent |last3=Suc |first4=Luis |last4=Busta |first5=Guadalupe |last5=Lizana |first6=Leopoldo |last6=Infante |first7=Santiago |last7=Royo |display-authors=1 |volume=815 |issue=2 |at=L29 |date=December 2015 |doi=10.1088/2041-8205/815/2/L29 |bibcode=2015ApJ...815L..29G |arxiv=1512.01095|s2cid=31114340 }} The same authors also say that Malin 1 is larger than thought, with another estimated diameter of around {{convert|750000|ly|pc|lk=on}}.