2017ApJ...839...46S


C.D.S. - SIMBAD4 rel 1.7 - 2020.10.21CEST15:41:07

2017ApJ...839...46S - Astrophys. J., 839, 46-46 (2017/April-2)

NuSTAR and Swift observations of the ultraluminous X-ray source IC 342 X-1 in 2016: witnessing spectral evolution.

SHIDATSU M., UEDA Y. and FABRIKA S.

Abstract (from CDS):

We report on an X-ray observing campaign of the ultraluminous X-ray source IC 342 X-1 with NuSTAR and Swift in 2016 October, in which we captured the very moment when the source showed spectral variation. The Swift/XRT spectrum obtained in October 9-11 has a power-law shape and is consistent with those observed in the coordinated XMM-Newton and NuSTAR observations in 2012. In October 16-17, when the 3-10 keV flux became ≃4 times higher, we performed simultaneous NuSTAR and Swift observations. In this epoch, the source showed a more round-shaped spectrum like that seen with ASCA23 years ago. Thanks to the wide energy coverage and high sensitivity of NuSTAR, we obtained hard X-ray data covering up to ∼30 keV for the first time during the high-luminosity state of IC 342 X-1. The observed spectrum has a broader profile than the multi-color disk blackbody model. The X-ray flux decreased again in the last several hours of the NuSTAR observation, when the spectral shape approached those seen in 2012 and 2016 October 9-11. The spectra obtained in our observations and in 2012 can be commonly described with disk emission and its Comptonization in cool (Te ≃ 4 keV), optically thick (τ ≃ 5) plasma. The spectral turnover seen at around 5-10 keV shifts to higher energies as the X-ray luminosity decreases. This behavior is consistent with that predicted from recent numerical simulations of super-Eddington accretion flows with Compton-thick outflows. We suggest that the spectral evolution observed in IC 342 X-1 can be explained by a smooth change in mass-accretion rate.

Abstract Copyright: © 2017. The American Astronomical Society. All rights reserved.

Journal keyword(s): accretion, accretion disks - black hole physics - X-rays: binaries - X-rays: individual: IC 342 X-1 - X-rays: individual: IC 342 X-1

Simbad objects: 8

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Number of rows : 8

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 RX J031820.3-662911 UX? 03 18 20.00 -66 29 10.9           ~ 171 1
2 2E 756 ULX 03 18 22.00 -66 36 04.3   23.5 23.6     O9.5 192 3
3 [SST2011] J034555.61+680455.3 ULX 03 45 55.612 +68 04 55.29           ~ 141 1
4 IC 342 SBG 03 46 48.514 +68 05 45.98   10.5       ~ 1395 1
5 RX J0957.9+6903 ULX 09 57 53.290 +69 03 48.20           ~ 200 4
6 [FK2005] 23 ULX 13 29 38.62 +58 25 05.6           ~ 109 2
7 V* V1033 Sco HXB 16 54 00.137 -39 50 44.90   15.20 14.2 16.14   F5IV 1719 1
8 Granat 1915+105 LXB 19 15 11.54938 +10 56 44.7585           ~ 2310 0

    Equat.    Gal    SGal    Ecl

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2020.10.21-15:41:07

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