The obscured X-ray binaries V404 Cyg, Cyg X-3, V4641 Sgr, and GRS 1915+105

Abstract

V404 Cyg, Cyg X-3, V4641 Sgr, and GRS 1915+105 are among the brightest X-ray binaries and display complex behavior in their multiwavelength emission. Apart from Cyg X-3, the other three sources have large accretion disks, and there is evidence of a high orbital inclination. Therefore, any large scale geometrical change in the accretion disk can cause local obscuration events. On the other hand, Cyg X-3 orbits its Wolf-Rayet companion star inside the heavy stellar wind obscuring the X-ray source. We study here whether the peculiar X-ray spectra observed from all four sources can be explained by local obscuration events. We fit the source spectra with two physically motivated models describing either a scenario where all the intrinsic emission is reprocessed in the surrounding matter or where the emitter is surrounded by a thick torus with variable opening angle. We show that the X-ray spectra during specific times are similar in all four sources likely arising from the high-density environments where they are embedded. The fitted models suggest that a low-luminosity phase preceding an intense flaring episode in the 2015 outburst of V404 Cyg is heavily obscured, but intrinsically very bright (super-Eddington) accretion state. Similar spectral evolution to that of V404 Cyg is observed from the recent, unusually low-luminosity state of GRS 1915+105. The modeling results point to a geometry change in the (outflowing) obscuring matter in V404 Cyg and GRS 1915+105, which is also linked to the radio (jet) evolution. All sources display obscured X-ray emission but with different intrinsic luminosities which points towards different factors causing the obscuration. This work highlights the importance of taking into account the reprocessing of the X-ray emission in the surrounding medium in the modeling of the X-ray spectra that may well take place in other sources as well.

24 pages, 14 figures, 8 tables. Accepted for publication in A&A. Abstract slightly abridged to meet ArXiv size limit

References in corpus (16)

• The role of the reflection fraction in constraining black hole spin
• A Parallax Distance to the Microquasar GRS 1915+105 and a Revised Estimate of its Black Hole Mass
• No Time for Dead Time: Timing analysis of bright black hole binaries with NuSTAR
• A rapidly-changing jet orientation in the stellar-mass black hole V404 Cygni
• The NuSTAR View of Nearby Compton-thick AGN: The Cases of NGC 424, NGC 1320 and IC 2560
• Swift observations of V404 Cyg during the 2015 outburst: X-ray outflows from super-Eddington accretion
• Effects of the stellar wind on X-ray spectra of Cygnus X-3
• The nature of the hard state of Cygnus X-3
• Spectroscopic evidence for a low-mass black hole in SWIFT J1753.5-0127
• Gemini/GNIRS infrared spectroscopy of the Wolf-Rayet stellar wind in Cygnus X-3
• Cygnus X-3: Its Little Friend's Counterpart, the Distance to Cygnus X-3, and Outflows/Jets
• A Delayed Transition to the Hard State for 4U 1630-47 at the End of Its 2010 Outburst
• NuSTAR observations of the Transient Galactic Black Hole Binary Candidate Swift J1858.6-0814: A New Sibling of V404 Cyg and V4641 Sgr?
• Photoionization Emission Models for the Cyg X-3 X-ray Spectrum
• The aperiodic broad-band X-ray variability of Cygnus X-3
• Optical and X-ray Correlations During the 2015 Outburst of the Black Hole V404 Cyg

Cited by in corpus (28)

• On the multi-wavelength variability of Mrk 110: Two components acting at different timescales
• A Systematic View of Ten New Black Hole Spins
• An Obscured, Seyfert-2-like State of the Stellar-mass Black Hole GRS 1915+105 Caused by Failed Disk Winds
• Low-Mass X-ray Binaries
• Ultra-High-Energy Gamma-Ray Bubble around Microquasar V4641 Sgr
• Observations of a radio-bright, X-ray obscured GRS 1915+105
• A NICER View of a Highly-Absorbed Flare in GRS 1915+105
• A shared accretion instability for black holes and neutron stars
• A study of natural frequencies in a dynamic corona-disk system
• The INTEGRAL view on Black Hole X-ray Binaries
• Discovery of thermonuclear (Type I) X-ray bursts in the X-ray binary Swift J1858.6-0814 observed with NICER and NuSTAR
• Relativistic X-Ray Reflection and Photoionised Absorption in the Neutron-Star Low-Mass X-ray Binary GX 13+1
• Dips and eclipses in the X-ray binary Swift J1858.6-0814 observed with NICER
• ALMA/NICER observations of GRS 1915+105 indicate a return to a hard state
• Wideband Study of the Brightest Black Hole X-ray Binary 4U 1543-47 in the 2021 Outburst: Signature of Disk-Wind Regulated Accretion
• Sub-second periodic radio oscillations in a microquasar
• Insight-HXMT observations of a possible fast transition from jet to wind dominated state during a huge flare of GRS~1915+105
• High resolution X-ray spectroscopy of V4641 Sgr during its 2020 outburst
• MAXI and NuSTAR observations of the faint X-ray transient MAXI J1848-015 in the GLIMPSE-C01 Cluster
• X-ray spectral correlations in a sample of Low-mass black hole X-ray binaries in the hard state
• Black holes at cosmic dawn in the redshifted 21cm signal of HI
• GG Carinae: orbital parameters and accretion indicators from phase-resolved spectroscopy and photometry
• Time resolved spectroscopy of a GRS 1915+105 flare during its unusual low state using AstroSat
• Likely detection of magnetic field related LFQPO in the soft X-ray re-brightening of GRS~1915+105
• A large misalignment between continuous jet and discrete ejecta in microquasar GRS 1915+105 during its obscured phase
• Dimming GRS 1915+105 observed with NICER and Insight--HXMT
• Reprocessing from highly ionized gas in the soft spectral state of V4641 Sgr with NuSTAR
• Exploring the accretion-ejection geometry of GRS 1915+105 in the obscured state with future X-ray spectro-polarimetry