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Title: A DISTANT ECHO OF MILKY WAY CENTRAL ACTIVITY CLOSES THE GALAXY’s BARYON CENSUS

Abstract

We report on the presence of large amounts of million-degree gas in the Milky Way’s interstellar and circum-galactic medium. This gas (1) permeates both the Galactic plane and the halo, (2) extends to distances larger than 60–200 kpc from the center, and (3) its mass is sufficient to close the Galaxy’s baryon census. Moreover, we show that a vast, ∼6 kpc radius, spherically symmetric central region of the Milky Way above and below the 0.16 kpc thick plane has either been emptied of hot gas or the density of this gas within the cavity has a peculiar profile, increasing from the center up to a radius of ∼6 kpc, and then decreasing with a typical halo density profile. This, and several other converging pieces of evidence, suggest that the current surface of the cavity, at 6 kpc from the Galaxy’s center, traces the distant echo of a period of strong nuclear activity of our supermassive black hole, occurring about 6 Myr ago.

Authors:
;  [1];  [2];  [3];  [4]
  1. Osservatorio Astronomico di Roma–INAF, Via di Frascati 33, I-00040 Monte Porzio Catone, RM (Italy)
  2. Instituto de Astronomia, Universidad Nacional Autonoma de Mexico, Mexico City (Mexico)
  3. Ohio State University, Columbus, OH (United States)
  4. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS-04, Cambridge, MA 02138 (United States)
Publication Date:
OSTI Identifier:
22654232
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal Letters
Additional Journal Information:
Journal Volume: 828; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 2041-8205
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BARYONS; BLACK HOLES; DENSITY; GALAXY NUCLEI; MASS; MILKY WAY; S CENTERS; SPHERICAL CONFIGURATION; SURFACES; SYMMETRY; X RADIATION

Citation Formats

Nicastro, F., Senatore, F., Krongold, Y., Mathur, S., and Elvis, M. A DISTANT ECHO OF MILKY WAY CENTRAL ACTIVITY CLOSES THE GALAXY’s BARYON CENSUS. United States: N. p., 2016. Web. doi:10.3847/2041-8205/828/1/L12.
Nicastro, F., Senatore, F., Krongold, Y., Mathur, S., & Elvis, M. A DISTANT ECHO OF MILKY WAY CENTRAL ACTIVITY CLOSES THE GALAXY’s BARYON CENSUS. United States. doi:10.3847/2041-8205/828/1/L12.
Nicastro, F., Senatore, F., Krongold, Y., Mathur, S., and Elvis, M. Thu . "A DISTANT ECHO OF MILKY WAY CENTRAL ACTIVITY CLOSES THE GALAXY’s BARYON CENSUS". United States. doi:10.3847/2041-8205/828/1/L12.
@article{osti_22654232,
title = {A DISTANT ECHO OF MILKY WAY CENTRAL ACTIVITY CLOSES THE GALAXY’s BARYON CENSUS},
author = {Nicastro, F. and Senatore, F. and Krongold, Y. and Mathur, S. and Elvis, M.},
abstractNote = {We report on the presence of large amounts of million-degree gas in the Milky Way’s interstellar and circum-galactic medium. This gas (1) permeates both the Galactic plane and the halo, (2) extends to distances larger than 60–200 kpc from the center, and (3) its mass is sufficient to close the Galaxy’s baryon census. Moreover, we show that a vast, ∼6 kpc radius, spherically symmetric central region of the Milky Way above and below the 0.16 kpc thick plane has either been emptied of hot gas or the density of this gas within the cavity has a peculiar profile, increasing from the center up to a radius of ∼6 kpc, and then decreasing with a typical halo density profile. This, and several other converging pieces of evidence, suggest that the current surface of the cavity, at 6 kpc from the Galaxy’s center, traces the distant echo of a period of strong nuclear activity of our supermassive black hole, occurring about 6 Myr ago.},
doi = {10.3847/2041-8205/828/1/L12},
journal = {Astrophysical Journal Letters},
issn = {2041-8205},
number = 1,
volume = 828,
place = {United States},
year = {2016},
month = {9}
}