Messier 82: 200 Years of Study

Messier 82: 200 years of study

Table Mountain Star Party 2015

Michael L Allen Messier 82 TMSPA ’15 1 / 22 What’s in a name? From the NASA Extragalactic Database (NED)

3C 231 [KWP81] 0951+69 11HUGS 167 4C +69.12 [DSL2000] 0951+700 [dML87] 745 87GB 095143.5+695452 [HRT2007] J095552+694047 [SPB93] 116 87GB[BWE91] 0951+6954 [JBB2007] J095552.72+694045.7 LGG 176:[G93] 012 [WB92] 0951+6954 2MASX J09555243+6940469 [M98j] 080 NED03 NVSS J095551+694046 IRAS 09517+6954 RX J0955.8+6940:[BEV98] 003 VLSS J0955.8+6940 IRAS F09517+6954 UITBOC 1644 6C B095143.6+695502 AKARI J0955536+694050 CXOU J095552.7+694045 8C 0951+699 AFGL 1388 CXOU J095552.8+694045 S4 0951+69 MESSIER 082 RX J0955.8+6940 CLASS J0955+6940 NGC 3034 1RXS J095550.4+694052 DA 277 UGC 05322 2PBC J0955.7+6941 NRAO 0341 ARP 337 SAXWFC J0955.6+6940.6 TXS 0951+699 CGCG 333-008 1AXG J095549+6940 GB6 J0955+6940 CGCG 0951.7+6955 1H 0950+696A HIJASS J0955+69 NED02 MCG +12-10-011 1ES 0951+699 RGB J0955+696 2MFGC 07685 [MHH96] J095550+694041 WMAP 088 PRC D-13 [SPS97] 08 WMAP J0955+6936 KTG 28B NGC 3031:[R97] 01 WMAP J095547+6935 KPG 218B [TSA98] J095541.25+693927.31 WMAP J095549+6935 LDCE 0842 NED005 MESSIER 082:[TOH2007] X-1 NEWPS 5yr 5s 233 HDCE 0552 NED003 NGC 3034:[MGS2012] 01 NEWPS 5yr 5s 15 226 Cigar Galaxy 2FGL J0955.9+6936 QVW5 J095527+6940 PGC 028655 1FGL J0956.5+6938 QVW7 J095540+694120 RBS 0809 WMAP3-NEWPS-5S 128 UZC J095557.0+694110

Michael L Allen Messier 82 TMSPA ’15 2 / 22 Where to ﬁnd M82

Michael L Allen Messier 82 TMSPA ’15 3 / 22 Where to ﬁnd M82

Michael L Allen Messier 82 TMSPA ’15 4 / 22 Who found M82

Figure: Johann Elert Bode Figure: Pierre M´echain Figure: Charles Messier (1747 - 1826) (1744 - 1804) (1730 - 1817)

Michael L Allen Messier 82 TMSPA ’15 5 / 22 From Charles Messier’s journal

“Nebula without star, near the preceding [M81]; both are appearing in the same ﬁeld of the telescope, this one is less distinct than the preceding; its light faint and elongated: at its extremity is a telescopic star. Seen at Berlin, by M. Bode, on December 31, 1774, and by M. M´echain in the month August 1779.”

- February 9, 1781

Michael L Allen Messier 82 TMSPA ’15 6 / 22 Early description of M82

“With a low power, No. 82 M. can be brought into the north part of the same ﬁeld of view [as M81], although they are half a degree apart. It is very long, narrow, and bright, especially at its northern limb, but rather paler than No. 81.

...The two nebulae precede Lambda, in the end of Draco’s tail, by 25deg, but as the vicinity is deﬁcient of large [bright] stars, they are not readily ﬁshed up. ” Figure: Adm. William Henry Smyth - writing in 1837 from Bedford, England (1788 - 1865)

Michael L Allen Messier 82 TMSPA ’15 7 / 22 Modern study

Allan Sandage (1926 - 2010) observational cosmologist worked on reﬁning the distance ladder, and the rate of expansion of the universe study of M82 revealed no resolvable stars with which to determine distance, and ﬁlaments of hydrogen gas being ejected near to escape velocity (Lynds & Sandage 1963)

Figure: KPNO 0.9m image H-alpha. Michael L Allen Messier 82 TMSPA ’15 8 / 22 Some theories concerning the disturbed appearance

1 “exploding” galaxy (Lynds & Sandage 1963) 2 an artifact of galaxy-galaxy collision (Baade & Minkowski 1954) 3 a manifestation of an active galactic nucleus (Burbidge & Burbidge 1960s) 4 collision with an intergalactic dust cloud (Elvius 1972) 5 star formation (various, 1970s)

Michael L Allen Messier 82 TMSPA ’15 9 / 22 Observations in support of the star formation hypothesis

existence of visible super star clusters strong infrared emission population of radio supernova remnants

Michael L Allen Messier 82 TMSPA ’15 10 / 22 Super star clusters

Bright, compact, so-called super star clusters (SSCs) dot the near-side face of M82, indicative of recent star formation.

Figure: HST/WFPC2 image of super star clusters in M82.

Michael L Allen Messier 82 TMSPA ’15 11 / 22 Super star clusters

Super star clusters (SSCs) contain between 104 and 106 stars and are thought to be an early stage in the formation of globular clusters, although formally they are classed as open clusters. A local SSC is the R136 cluster whose light powers the Tarantula Nebula in the LMC.

Figure: A local super star cluster: R136 in the LMC (HST 3-ﬁlter composite image).

Michael L Allen Messier 82 TMSPA ’15 12 / 22 Strong infrared emission

Infrared light in galaxies is produced when visible star light is absorbed by dust grains and then re-emitted as infrared. The total power in the infrared should closely match the total power of star light.

Figure: Production of infrared light in galaxies.

Michael L Allen Messier 82 TMSPA ’15 13 / 22 Strong infrared emission

The so-called infrared excess emission, seen at the extreme right-hand side of this image where the data points are located above the dust emission spectrum (dashed line), indicate the presence of dust raised to high temperatures by light from hot young stars.

Figure: A spectrum of M82: brightness (vertical) versus color (horizontal) in the range from radio (left) to infrared (right); data from Klein et al. (1988).

Michael L Allen Messier 82 TMSPA ’15 14 / 22 Population of radio supernova remnants

A radio supernova remnant (SNR) is the expanding gas cloud ejected from a star following core collapse. In M82, young SNRs (point sources) are strictly conﬁned in a high pressure bath of interstellar gas (diﬀuse emission). The historical SN Figure: Young SNRs dot the interior of rate may have been as high as once M82 in this 3cm VLA image from Allen per decade. The aggregate energy (1999). from collections of supernovae propel gas out of the galactic disk.

Michael L Allen Messier 82 TMSPA ’15 15 / 22 A model of the outﬂow

Michael L Allen Messier 82 TMSPA ’15 16 / 22 A model of the outﬂow

Michael L Allen Messier 82 TMSPA ’15 17 / 22 A model of the outﬂow

The signature of this process is layers of gas from very hot to very cold, all within the disk of the galaxy.

Michael L Allen Messier 82 TMSPA ’15 18 / 22 What caused the star elevated formation?

A bridge of neutral hydrogen was discovered by Cottrell (1977) using the Cambridge Half-Mile radio telescope. The evidence suggests a close tidal interaction With M81 about 107 years ago. Although M81 is the more massive galaxy, M82 is more compact, meaning that M81 lost gas to M82 to fuel a vigorous Figure: A bridge of neutral hydrogen but brief episode of star formation. connects three galaxies in this VLA image by Yun et al. (1994).

Michael L Allen Messier 82 TMSPA ’15 19 / 22 M82 as the starburst prototype

1 starburst: if star formation continued, M82’s entire supply of interstellar gas would be consumed in less than the current age of the universe 2 its light is dominated by events related to star formation, thus makes a good candidate to study star formation statistically 3 all galaxies are thought to have had starburst episodes early in their histories, potentially making M82 a local analog of very high redshift galaxies 4 the starburst in M82 is highly evolved, i.e., is ending: little new star formation, no new SNR candidates despite several decades of monitoring (note: SN 2014J was Type Ia, not associated with star formation)

Michael L Allen Messier 82 TMSPA ’15 20 / 22 Some notes about the presentation

Historical images are from Wikipedia.

Astronomical data & image retrieval are from the NASA Extragalactic database (NED).

Astronomical abstract retrieval is from SAO/NASA Astrophysics Data System (ADS).

Processing of astronomical images was performed with SAOimage DS9.

Original drawings completed in xﬁg.

The presentation was typeset in LaTeX using the Beamer package in an emacs editor on Linux Fedora 21.

Michael L Allen Messier 82 TMSPA ’15 21 / 22 Thanks for coming

... and keep looking up!

Michael L Allen Messier 82 TMSPA ’15 22 / 22