astrobites
galaxies
The Whirlpool Galaxy Like You’ve Never Seen it Before
It’s big, it’s active, and it’s only 20 million lightyears away– it is the Whirlpool galaxy, and astronomers are getting a brand new view. Using the Plateau de Bure interferometer, this paper examines the gas in this nearby grand-design spiral galaxy on arcsecond scales, resolving for the first time its individual molecular clouds. What does this tell us about star formation in this galaxy? Stay tuned!
Digging up “red nuggets” in local elliptical galaxies
Huang et al. dig up evidence that distant “red nugget” galaxies grew into the massive ellipticals we see today by consuming smaller, gas-poor galaxies.
Moving mesh code AREPO may help us understand galaxy evolution better than before
Moving mesh code AREPO looks like it will help astronomers understand the physics of galaxy formation and evolution better than its predecessors, due to an innovative new method of solving the fluid dynamics equations in astrophysical settings. This paper discusses the differences between AREPO and another code called GADGET in the case of gas accretion onto galaxies.
Seeing Galaxy formation before reionization: baryon-dark matter relative velocity helps!
Relative velocity in the early Universe between regular matter (baryons) and dark matter enhances an otherwise hard-to-detect signal and makes it likely we can look back even farther into the past.
The Spinning Black Hole at the Center of NGC 1365
Previous authors have claimed that the black hole at the center of NGC 1365 is spinning extremely rapidly. But these claims are based on certain assumptions about the dominance of relativistic effects on the spectrum of NGC 1365. Risaliti et al., dig deeper into the spectral data of this X-ray source and use simulations to determine whether the signatures we see are caused by a rapidly-spinning black hole, or just cloudy (galactic) weather.
Evidence for a Universal IMF from a Dwarf Galaxy
Hubble observations of a nearby galaxy show evidence for a universal initial mass function.
Mapping star formation in galaxies using slitless spectroscopy
A team of astronomers working on the 3D-HST survey make use of the Hubble Space Telescope’s grism to observe star formation as a function of radius in a large sample of galaxies at intermediate redshift.
Active Galactic Nuclei: How to Stop Star Formation
The authors investigate the fraction of massive galaxies at z ~ 2 that contains an Active Galactic Nucleus (AGN), in hopes of understanding the importance of AGN in quenching star formation.
Separating AGN activity from star formation at high redshift
Using new data from the MOSFIRE spectrograph, the authors of this paper test the ability of classic emission line diagnostics to separate star formation activity from supermassive black hole accretion at high redshift. What they find may be important for understanding how the growth galaxies and black holes affect one another over cosmic time.
Introducing: The Over-massive Black Hole
Weighing in at 17 billion solar masses, NGC 1277 contains the largest black hole discovered to date. What makes this black hole exceptional it not just its size, but also that it does not seem to follow the relationship between most supermassive black holes and their host galaxies known as the M-sigma relation. The author’s discuss their findings and possible implications.
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