Constraining sterile neutrino warm dark matter with Chandra observations of the Andromeda galaxy
- Casey R. Watson, Zhiyuan Li, Nicholas K. Polley
- Physics
- 17 November 2011
We use the Chandra unresolved X-ray emission spectrum from a 12'–28' (2.8–6.4 kpc) annular region of the Andromeda galaxy to constrain the radiative decay of sterile neutrino warm dark matter. By…
THE PANCHROMATIC HUBBLE ANDROMEDA TREASURY. VII. THE STEEP MID-ULTRAVIOLET TO NEAR-INFRARED EXTINCTION CURVE IN THE CENTRAL 200 pc OF THE M31 BULGE
- Hui Dong, Zhiyuan Li, L. Bianchi
- Physics
- 11 March 2014
We measure the extinction curve in the central 200 pc of M31 at mid-ultraviolet to near-infrared wavelengths (from 1928 Å to 1.5 μm), using Swift/UVOT and Hubble Space Telescope (HST) Wide Field…
M31* and its circumnuclear environment
- Zhiyuan Li, Q. Wang, B. Wakker
- Physics
- 23 February 2009
We present a multiwavelength investigation of the circumnuclear environment of the Andromeda galaxy (M31), utilizing archival Chandra, FUSE, GALEX, HST and Spitzer data as well as ground-based…
Chandra Detection of Diffuse Hot Gas in and around the M31 Bulge
- Zhiyuan Li, Q. Wang
- Physics
- 22 August 2007
We report the detection of diffuse hot gas in M31, using archival Chandra observations that allow us to map out a 30′ × 30′ field (covering a galactocentric radius up to 4.5 kpc) and to detect…
X-ray spectroscopy of the hot gas in the M31 bulge
- Jiren Liu, Daniel Wang, Zhiyuan Li, J. Peterson
- Physics
- 22 January 2010
We present an X-ray spectroscopic study of the nuclear region of the M31 bulge, based on observations of the XMM–Newton Reflection Grating Spectrometers. The obtained high-resolution grating spectra…
EVIDENCE FOR A PARSEC-SCALE JET FROM THE GALACTIC CENTER BLACK HOLE: INTERACTION WITH LOCAL GAS
- Zhiyuan Li, M. Morris, F. Baganoff
- Physics
- 1 October 2013
Despite strong physical reasons that they should exist and decades of searching, jets from the Galactic center black hole, Sgr A*, have not yet been convincingly detected. Based on high-resolution…
EXPLORING THE UNUSUALLY HIGH BLACK-HOLE-TO-BULGE MASS RATIOS IN NGC 4342 AND NGC 4291: THE ASYNCHRONOUS GROWTH OF BULGES AND BLACK HOLES
We study two nearby early-type galaxies, NGC 4342 and NGC 4291, that host unusually massive black holes relative to their low stellar mass. The observed black-hole-to-bulge mass ratios of NGC 4342…
DEEP CHANDRA OBSERVATIONS OF A2199: THE INTERPLAY BETWEEN MERGER-INDUCED GAS MOTIONS AND NUCLEAR OUTBURSTS IN A COOL CORE CLUSTER
- P. Nulsen, Zhiyuan Li, S. Murray
- Physics
- 30 July 2013
We present new Chandra observations of A2199 that show evidence of gas sloshing due to a minor merger, as well as impacts of the radio source, 3C 338, hosted by the central galaxy, NGC 6166, on the…
Chandra and XMM–Newton detection of large-scale diffuse X-ray emission from the Sombrero galaxy
- Zhiyuan Li, Q. Wang, S. Hameed
- Physics
- 17 January 2007
We present an X-ray study of the massive edge-on Sa galaxy, Sombrero (M 104; NGC 4594), based on XMM-Newton and Chandra observations. A list of 62 XMM-Newton and 175 Chandra discrete X-ray sources is…
A Chandra Survey of Milky Way Globular Clusters. I. Emissivity and Abundance of Weak X-Ray Sources
- Z. Cheng, Zhiyuan Li, Xiao-jie Xu, Xiangdong Li
- Physics
- 27 March 2018
Based on archival Chandra data, we have carried out an X-ray survey of 69, or nearly half the known population of, Milky Way globular clusters (GCs), focusing on weak X-ray sources, mainly…
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