* Astronomy

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Cigar Galaxy

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M82 galaxy

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RE: Messier 82

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NASA's RXTE Satellite Decodes the Rhythm of an Unusual Black Hole

Astronomers have uncovered rhythmic pulsations from a rare type of black hole 12 million light-years away by sifting through archival data from NASA's Rossi X-ray Timing Explorer (RXTE) satellite.
The signals have helped astronomers identify an unusual midsize black hole called M82 X-1, which is the brightest X-ray source in a galaxy known as Messier 82. Most black holes formed by dying stars are modestly-sized, measuring up to around 25 times the mass of our sun. And most large galaxies harbor monster, or supermassive, black holes that contain tens of thousands of times more mass.
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NGC 3034

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RE: Messier 82

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Title: AKARI near-infrared spectroscopy of the aromatic and aliphatic hydrocarbon emission features in the galactic superwind of M 82
Authors: M. Yamagishi, H. Kaneda, D. Ishihara, T. Kondo, T. Onaka, T. Suzuki, Y. C. Minh

Aims. We investigate the properties of hydrocarbon grains in the galactic superwind of M 82.
Methods. With AKARI, we performed near-infrared (2.5 - 4.5 um) spectroscopic observations of 34 regions in M 82 including its northern and southern halos.
Results. Many of the spectra show strong emission at 3.3 um due to polycyclic aromatic hydrocarbons (PAHs) and relatively weak features at 3.4 - 3.6 um due to aliphatic hydrocarbons. In particular, we clearly detect the PAH 3.3 um emission and the 3.4 - 3.6 um features in halo regions, which are located at a distance of 2 kpc away from the galactic center. We find that the ratios of the 3.4 - 3.6 um features to the 3.3 um feature intensity significantly increase with distance from the galactic center, while the ratios of the 3.3 um feature to the AKARI 7 um band intensity do not.
Conclusions. Our results clearly confirm the presence of small PAHs even in a harsh environment of the halo of M 82. The results also reveal that the aliphatic hydrocarbons emitting the 3.4 - 3.6 um features are unusually abundant in the halo, suggesting that small carbonaceous grains are produced by shattering of larger grains in the galactic superwind.

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Messier 82 - from kleinfriesen observatory

Credit Ramonkfo

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Title: Measurement of the Mass and Stellar Population Distribution in M82 with the LBT
Authors: Johnny P. Greco, Paul Martini, Todd A. Thompson

We present a K-band spectroscopic study of the stellar and gas kinematics, mass distribution, and stellar populations of the archetypical starburst M82. We used the CO stellar absorption bandhead at 2.29 {\mu}m (CO_2.29) to measure the rotation curve out to nearly 4 kpc radius on both the eastern and western sides of the galaxy. In contrast with the nearly Keplerian gas dynamics suggested by previous measurements of HI and CO emission from the ISM, which imply a truncation in M82's dark matter halo, our data show that the rotation curve is in fact flat on 1 - 4 kpc scales. The kinematics of the Br{\gamma}, H2, and HeI emission lines are consistent with, although characterized by slightly higher velocities than, the stellar kinematics. We derived M82's mass distribution from our stellar kinematic measurements and estimate its total dynamical mass is ~10^10 solar masses. We measured the equivalent width of CO_2.29 (W_2.29) as a function of distance from the center of the galaxy to investigate the spatial extent of the red supergiant (RSG) population. The variation in W_2.29 with radius clearly shows that RSGs dominate the light inside 500 pc radius. M82's famous superwind is likely launched from this region, where we estimate the enclosed mass is <= 2 z 10^9 solar masses.