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The Galactic Center 50 km s$^{-1}$ Molecular Cloud (50MC) is the most remarkable molecular cloud in the Sagittarius A region. This cloud is a candidate for the massive star formation induced by cloud-cloud collision (CCC) with a collision…

Astrophysics of Galaxies · Physics 2019-03-07 Kenta Uehara , Masato Tsuboi , Yoshimi Kitamura , Ryosuke Miyawaki

We study the heating of the intergalactic medium (IGM) surrounding high redshift star forming galaxies due to cosmic rays (CR). We take into account the diffusion of low energy cosmic rays and study the patchiness of the resulting heating.…

Cosmology and Nongalactic Astrophysics · Physics 2020-07-31 Ranita Jana , Biman B. Nath

The chemistry of shielded molecular gas is primarily driven by energetic, charged particles dubbed cosmic rays (CRs), in particular those with energies under 1 GeV. CRs ionize molecular hydrogen and helium, the latter of which contributes…

Astrophysics of Galaxies · Physics 2026-04-01 Arghyadeb Roy , Brandt A. L. Gaches , Jonathan C. Tan

Our study focuses on characterizing the highly ionized gas within the Milky Way's (MW) Circumgalactic Medium (CGM) that gives rise to ionic transitions in the X-ray band 2 - 25 \AA. Utilizing stacked \Chandra/\ACISS\ \MEG\ and \LETG\…

Astrophysics of Galaxies · Physics 2024-07-25 Armando Lara-DI , Yair Krongold , Smita Mathur , Sanskriti Das , Anjali Gupta , O. Segura Montero

The cores of most galaxies are thought to harbour supermassive black holes, which power galactic nuclei by converting the gravitational energy of accreting matter into radiation (ref 1). Sagittarius A*, the compact source of radio, infrared…

Cosmic rays are predominantly accelerated in shocks associated with star formation such as supernova remnants and stellar wind bubbles, so the cosmic-ray flux and thus cosmic-ray ionization rate, $\zeta_{\rm H}$, should correlate with the…

Astrophysics of Galaxies · Physics 2018-10-02 Nick Indriolo , E. A. Bergin , E. Falgarone , B. Godard , M. A. Zwaan , D. A. Neufeld , M. G. Wolfire

EGRET data on the Gamma ray emission from the inner Galaxy have shown a rather flat spectrum, extending to about 50 GeV. It is usually assumed that these gamma-rays arise from the interactions of cosmic ray nuclei with ambient matter.…

Astrophysics · Physics 2007-05-23 Wolfgang Rhode , Torsten A. Ensslin , Peter L. Biermann

The central molecular zone (CMZ) hosts some of the most massive and dense molecular clouds and star clusters in the Galaxy, offering an important window into star formation under extreme conditions. Star formation in this extreme…

Astrophysics of Galaxies · Physics 2017-02-22 J. D. Henshaw

We present infrared and millimeter observations of molecular gas, dust and ionized gas towards a sample of clouds distributed along the 500 central pc of the Galaxy. The clouds were selected to investigate the physical state, in particular…

Astrophysics · Physics 2009-11-07 N. J. Rodriguez-Fernandez , J. Martin-Pintado , A. Fuente , T. L. Wilson

The innermost region of the Milky Way harbors the central molecular zone (CMZ). This region contains a large amount of molecular gas but a poor star formation rate considering the densities achieved by the gas in this region. We used the…

Astrophysics of Galaxies · Physics 2025-01-29 Leonardo Chaves-Velasquez , Gilberto C. Gómez , Ángeles Pérez-Villegas

We analyze deep near-IR adaptive optics imaging as well as new proper motion data of the nuclear star cluster of the Milky Way. The surface density distribution of faint stars peaks within 0.2" of the black hole candidate SgrA*. The radial…

We investigate star formation at very early evolutionary phases in five massive clouds in the inner 500 pc of the Galaxy, the Central Molecular Zone. Using interferometer observations of H$_2$O masers and ultra-compact H II regions, we find…

The circumnuclear disk (CND) of the Galactic Center is exposed to many energetic phenomena coming from the supermassive black hole Sgr A* and stellar activities. These energetic activities can affect the chemical composition in the CND by…

Recent HESS observations of the ~200 pc scale diffuse gamma-ray emission from the central molecular zone (CMZ) suggest the presence of a PeV cosmic-ray accelerator (PeVatron) located in the inner 10 pc region of the Galactic Center.…

High Energy Astrophysical Phenomena · Physics 2016-12-28 Ruo-Yu Liu , Xiang-Yu Wang , Anton Prosekin , Xiao-Chuan Chang

The Central Molecular Zone (CMZ; the central ~ 500 pc of the Galaxy) is a kinematically unusual environment relative to the Galactic disc, with high velocity dispersions and a steep size-linewidth relation of the molecular clouds. In…

We present a map of the major part of the central molecular zone (CMZ) of simultaneous observations in the NH3 (J,K) = (1,1) and (2,2) lines using the Kagoshima 6-m telescope. The mapped area is -1.000 < l < 1.625 deg, -0.375 < b < +0.250…

The inner few parsecs at the Galactic Center have come under intense scrutiny in recent years, in part due to the exciting broad-band observations of this region, but also because of the growing interest from theorists motivated to study…

Astrophysics · Physics 2009-11-06 Fulvio Melia , Heino Falcke

We present JWST-NIRCam narrow-band, 4.05 $\mu$m Brackett-$\alpha$ images of the Sgr C HII region, located in the Central Molecular Zone (CMZ) of the Galaxy. Unlike any HII region in the Solar vicinity, the Sgr C plasma is dominated by…

The supermassive black hole (SMBH), Sgr A*, at the Galactic Center is surrounded by a molecular circumnuclear disk (CND) lying between 1.5-4 pc radii. The irregular and clumpy structures of the CND, suggest dynamical evolution and episodic…

Astrophysics of Galaxies · Physics 2015-06-05 Hauyu Baobab Liu , Pei-Ying Hsieh , Paul T. P. Ho , Yu-Nung Su , Melvyn Wright , Ai-Lei Sun , Young Chol Minh