Revealing the nature of the ULX and X-ray population of the spiral galaxy NGC 4088

We present the first Chandra and Swift X-ray study of the spiral galaxy NGC 4088 and its ultraluminous X-ray source (ULX N4088-X1). We also report very long baseline interferometry (VLBI) observations at 1.6 and 5 GHz performed quasi-simultaneously with the Swift and Chandra observations, respective...

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Main Authors: Mezcua, M., Fabbiano, G., Gladstone, J., Farrell, S., Soria, Roberto
Format: Journal Article
Published: Institute of Physics Publishing 2014
Subjects:
Online Access:http://hdl.handle.net/20.500.11937/37345
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author Mezcua, M.
Fabbiano, G.
Gladstone, J.
Farrell, S.
Soria, Roberto
author_facet Mezcua, M.
Fabbiano, G.
Gladstone, J.
Farrell, S.
Soria, Roberto
author_sort Mezcua, M.
building Curtin Institutional Repository
collection Online Access
description We present the first Chandra and Swift X-ray study of the spiral galaxy NGC 4088 and its ultraluminous X-ray source (ULX N4088-X1). We also report very long baseline interferometry (VLBI) observations at 1.6 and 5 GHz performed quasi-simultaneously with the Swift and Chandra observations, respectively. Fifteen X-ray sources are detected by Chandra within the D25 ellipse of NGC 4088, from which we derive the X-ray luminosity function (XLF) of this galaxy. We find the XLF is very similar to those of star-forming galaxies and estimate a star-formation rate of 4.5 M☉ yr–1. The Chandra detection of the ULX yields its most accurate X-ray position, which is spatially coincident with compact radio emission at 1.6 GHz. The ULX Chandra X-ray luminosity, L 0.2-10.0 keV = 3.4 × 1039 erg s–1, indicates that N4088-X1 could be located at the high-luminosity end of the high-mass X-ray binary (HMXB) population of NGC 4088. The estimates of the black hole (BH) mass and ratio of radio to X-ray luminosity of N4088-X1 rule out a supermassive BH nature. The Swift X-ray spectrum of N4088-X1 is best described by a thermal Comptonization model and presents a statistically significant high-energy cutoff. We conclude that N4088-X1 is most likely a stellar remnant BH in an HMXB, probably fed by Roche lobe overflow, residing in a super-Eddington ultraluminous state. The 1.6 GHz VLBI source is consistent with radio emission from possible ballistic jet ejections in this state.
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spelling curtin-20.500.11937-373452017-09-13T13:38:14Z Revealing the nature of the ULX and X-ray population of the spiral galaxy NGC 4088 Mezcua, M. Fabbiano, G. Gladstone, J. Farrell, S. Soria, Roberto radio continuum: general accretion accretion disks black hole physics X-rays: binaries ISM: jets and outflows We present the first Chandra and Swift X-ray study of the spiral galaxy NGC 4088 and its ultraluminous X-ray source (ULX N4088-X1). We also report very long baseline interferometry (VLBI) observations at 1.6 and 5 GHz performed quasi-simultaneously with the Swift and Chandra observations, respectively. Fifteen X-ray sources are detected by Chandra within the D25 ellipse of NGC 4088, from which we derive the X-ray luminosity function (XLF) of this galaxy. We find the XLF is very similar to those of star-forming galaxies and estimate a star-formation rate of 4.5 M☉ yr–1. The Chandra detection of the ULX yields its most accurate X-ray position, which is spatially coincident with compact radio emission at 1.6 GHz. The ULX Chandra X-ray luminosity, L 0.2-10.0 keV = 3.4 × 1039 erg s–1, indicates that N4088-X1 could be located at the high-luminosity end of the high-mass X-ray binary (HMXB) population of NGC 4088. The estimates of the black hole (BH) mass and ratio of radio to X-ray luminosity of N4088-X1 rule out a supermassive BH nature. The Swift X-ray spectrum of N4088-X1 is best described by a thermal Comptonization model and presents a statistically significant high-energy cutoff. We conclude that N4088-X1 is most likely a stellar remnant BH in an HMXB, probably fed by Roche lobe overflow, residing in a super-Eddington ultraluminous state. The 1.6 GHz VLBI source is consistent with radio emission from possible ballistic jet ejections in this state. 2014 Journal Article http://hdl.handle.net/20.500.11937/37345 10.1088/0004-637X/785/2/121 Institute of Physics Publishing fulltext
spellingShingle radio continuum: general
accretion
accretion disks
black hole physics
X-rays: binaries
ISM: jets and outflows
Mezcua, M.
Fabbiano, G.
Gladstone, J.
Farrell, S.
Soria, Roberto
Revealing the nature of the ULX and X-ray population of the spiral galaxy NGC 4088
title Revealing the nature of the ULX and X-ray population of the spiral galaxy NGC 4088
title_full Revealing the nature of the ULX and X-ray population of the spiral galaxy NGC 4088
title_fullStr Revealing the nature of the ULX and X-ray population of the spiral galaxy NGC 4088
title_full_unstemmed Revealing the nature of the ULX and X-ray population of the spiral galaxy NGC 4088
title_short Revealing the nature of the ULX and X-ray population of the spiral galaxy NGC 4088
title_sort revealing the nature of the ulx and x-ray population of the spiral galaxy ngc 4088
topic radio continuum: general
accretion
accretion disks
black hole physics
X-rays: binaries
ISM: jets and outflows
url http://hdl.handle.net/20.500.11937/37345