J/A+A/589/A116 Multiwavelength study of Sgr A* (Mossoux+, 2016)
Multiwavelength study of the flaring activity of Sgr A* in 2014 February-April.
Mossoux E., Grosso N., Bushouse H., Eckart A., Yusef-Zadeh F.,
Plambeck R.L., Peissker F., Valencia-S. M., Porquet D., Cotton W.D.,
Roberts D.A.
<Astron. Astrophys. 589, A116 (2016)>
=2016A&A...589A.116M 2016A&A...589A.116M (SIMBAD/NED BibCode)
ADC_Keywords: Milky Way; X-ray sources
Keywords: Galaxy: center - X-rays: individuals: Sgr A* -
radiation mechanisms: general
Abstract:
We present the results of the multiwavelength study of the flaring
activity of the supermassive black hole named Sgr A* is located at the
dynamical center of the Milky Way. We detected two X-ray flares on
2014 Mar. 10 and Apr. 2 with XMM-Newton, three near-infrared (NIR)
flares with HST on 2014 Mar. 10 and Apr. 2, and two NIR flares on 2014
Apr. 3 and 4 with VLT. The X-ray flare on 2014 Mar. 10 is
characterized by a long rise and a rapid decay. Its total duration is
one of the longest detected so far in X-rays. Its NIR counterpart
peaked well before the X-ray maximum, implying a dramatic change in
the X-ray-to-NIR flux ratio during this event. This NIR/X-ray flare is
interpreted as either a single flare where variation in the
X-ray-to-NIR flux ratio is explained by the adiabatic compression of a
plasmon, or two distinct flaring components separated by 1.2h with
simultaneous peaks in X-rays and NIR. We identified an increase in the
rising radio flux density at 13.37GHz on 2014 Mar. 10 with the VLA
that could be the delayed radio emission from a NIR/X-ray flare that
occurred before the start of our observation. The X-ray flare on 2014
Apr. 2 occurred for HST during the occultation of Sgr A* by the Earth,
therefore we only observed the start of its NIR counterpart. With NIR
synchrotron emission from accelerated electrons and assuming X-rays
from synchrotron self-Compton emission, the region of this NIR/X-ray
flare has a size of 0.03-7 times the Schwarzschild radius and an
electron density of 108.5-1010.2cm-3, assuming a synchrotron
spectral index of 0.3-1.5. When Sgr A* reappeared to the HST view, we
observed the decay phase of a distinct bright NIR flare with no
detectable counterpart in X-rays. On 2014 Apr. 3, two 95GHz flares
were observed with CARMA, where the first may be the delayed emission
of a NIR flare observed with VLT.
Description:
Sgr A* is closest supermassive black hole is known to have a
luminosity several orders of magnitude lower than the Eddington
luminosity. Flares coming from the Sgr A* environment can be observed
in infrared, X-ray, and submillimeter wavelengths, but their origins
are still debated. We studied the X-ray, infrared, and radio flaring
activity of Sgr A* close to the time of the Dusty S-cluster Object
(DSO)/G2 pericenter passage in order to constrain the physical
properties and origin of the flares. Simultaneous observations were
made with XMM-Newton and WFC3 onboard HST during the period Feb-Apr
2014, in addition to coordinated observations with SINFONI at ESO's
VLT, VLA in its A-configuration, and CARMA.
Objects:
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RA (2000) DE Designation(s)
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17 45 40.04 -29 00 28.2 Sgr A* = NAME Sgr A*
12 56 11.17 -05 47 21.5 3C 279 = RX J1256.1-0547
17 44 23.58 -31 16 36.3 1733-130 = QSO J1744-3116
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
fig2.dat 34 848 Sgr A* light curve obtained between 2 and 10keV
with XMM-Newton/EPIC (pn+MOS1+MOS2)
fig9.dat 39 2652 Sgr A* light curve in NIR (1.53µm) with HST
fig11.dat 39 39 Sgr A* light curve in NIR (2.2µm) with VLT
fig12.dat 38 2069 Sgr A* light curve at 95GHz with CARMA
fig13.dat 44 1703 Sgr A* light curve in radio (8.56, 13.37, 1.68
and 5.19GHz) with VLA
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See also:
J/A+A/502/91 : Proper motions of stars near SgrA* (Schoedel+, 2009)
J/A+A/511/A18 : NIR observations of stars near SgrA* (Schoedel+, 2010)
J/A+A/534/A117 : NIR polarimetry of sources near SgrA* (Buchholz+, 2011)
J/MNRAS/428/2731 : SgrA* emission at 7mm (Beaklini+, 2013)
J/A+A/582/A118 : OH-streamer in SgrA at 1665 and 1667MHz (Karlsson+, 2015)
Byte-by-byte Description of file: fig2.dat
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Bytes Format Units Label Explanations
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1- 10 A10 "date" Date Observation date
12- 22 F11.5 d MJD Center of the light curve bin in UTC (1)
24- 28 F5.3 ct/s CR Count rate in the light curve bin
30- 34 F5.3 ct/s e_CR Error on the count rate
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Note (1): The bin length is 300s, i.e., the start and stop times of the bin are
time-150s and time+150s, respectivelly.
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Byte-by-byte Description of file: fig9.dat
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Bytes Format Units Label Explanations
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1- 10 A10 "date" Date Observation date
12- 22 F11.5 d MJD Center of the light curve bin in UTC (1)
24- 28 F5.2 mJy FluxSgrA Flux density of Sgr A* in the light curve bin
30- 34 F5.2 mJy FluxRef Flux density of the reference star in the
light curve bin
36- 39 F4.2 mJy e_FluxRef Error on the flux density (2)
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Note (1): The bin length is 25s, i.e., the start and stop times of the bin are
time-12.5s and time+12.5s, respectivelly.
Note (2): The error is the standard deviation of the flux density of the
reference star
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Byte-by-byte Description of file: fig11.dat
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Bytes Format Units Label Explanations
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1- 10 A10 "date" Date Observation date
12- 27 F16.10 d MJD Center of the light curve bin in UTC (1)
29- 33 F5.3 --- FRatio Sgr A*-to-S2 flux density ratio
35- 39 F5.3 --- e_FRatio Error on the Sgr A*-to-S2 flux density ratio
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Note (1): The bin length is 400s, i.e., the start and stop times of the bin are
time-200s and time+200s, respectivelly.
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Byte-by-byte Description of file: fig12.dat
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Bytes Format Units Label Explanations
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1- 10 A10 "date" Date Observation date
12- 22 F11.5 d MJD Center of the light curve bin in UTC (1)
24- 29 F6.3 Jy Flux Flux density in the light curve bin
31- 38 A8 --- Source Observed source (2)
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Note (1): The bin length is 10s, i.e., the start and stop times of the bin are
time-5s and time+5s, respectivelly.
Note (2): 1733-130 and 3C279 are the reference sources
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Byte-by-byte Description of file: fig13.dat
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Bytes Format Units Label Explanations
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1- 10 A10 "date" Date Observation date
12- 22 F11.5 d MJD Center of the light curve bin in UTC (1)
24- 30 F7.5 Jy Flux Flux density in the light curve bin
32- 38 F7.5 Jy e_Flux Error on the flux density
40- 44 F5.2 GHz Freq Observed frequency (1.68, 5.19, 8.56 and 13.37)
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Note (1): The bin length is 30s, i.e., the start and stop times of the bin are
time-15s and time+15s, respectivelly.
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Acknowledgements:
Enmanuelle Mossoux, enmanuelle.mossoux(at)astro.unistra.fr
(End) E. Mossoux [Strasbourg, France], P. Vannier [CDS] 30-Mar-2016