Suzaku Observations of 4U 1957+11: Potentially the Most Rapidly Spinning Black Hole in (the Halo of) the Galaxy

Abstract

We present three Suzaku observations of the black hole candidate 4U 1957+11 (V1408 Aql) --- a source that exhibits some of the simplest and cleanest examples of soft, disk-dominated spectra. 4U 1957+11 also presents among the highest peak temperatures found from disk-dominated spectra. Such temperatures may be associated with rapid black hole spin. The 4U 1957+11 spectra also require a very low normalization, which can be explained by a combination of small inner disk radius and a large distance (>10 kpc) which places 4U 1957+11 well into the Galactic halo. We perform joint fits to the Suzaku spectra with both relativistic and Comptonized disk models. Assuming a low mass black hole and the nearest distance (3 M_sun, 10 kpc), the dimensionless spin parameter a* = Jc/GM^2 >~ 0.9. Higher masses and farther distances yield a*~1. Similar conclusions are reached with Comptonization models; they imply a combination of small inner disk radii (or, equivalently, rapid spin) and large distance. Low spin cannot be recovered unless 4U 1957+11 is a low mass black hole that is at the unusually large distance of >~ 40 kpc. We speculate whether the suggested maximal spin is related to how the system came to reside in the halo.

To be published in the Astrophysical Journal

References in corpus (7)

• Testing Accretion Disk Theory in Black Hole X-ray Binaries
• A Grid of Relativistic, non-LTE Accretion Disk Models for Spectral Fitting of Black Hole Binaries
• Corona, Jet, and Relativistic Line Models for Suzaku/RXTE/Chandra-HETG Observations of the Cygnus X-1 Hard State
• Testing the jet quenching paradigm with an ultradeep observation of a steadily soft state black hole
• Runaway and hypervelocity stars in the Galactic halo: Binary rejuvenation and triple disruption
• Limits on Hot Galactic Halo Gas from X-ray Absorption Lines
• Disk Dominated States of 4U 1957+11: Chandra, XMM, and RXTE Observations of Ostensibly the Most Rapidly Spinning Galactic Black Hole

Cited by in corpus (33)

• BlackCAT: A catalogue of stellar-mass black holes in X-ray transients
• WATCHDOG: A Comprehensive All-Sky Database of Galactic Black Hole X-ray Binaries
• Black Hole Spin via Continuum Fitting and the Role of Spin in Powering Transient Jets
• The First LHAASO Catalog of Gamma-Ray Sources
• Spinning Black Hole Binary Dynamics, Scattering Amplitudes and Effective Field Theory
• Next-to-next-to-leading order spin-orbit effects in the gravitational wave flux and orbital phasing of compact binaries
• Next-to-next-to-leading order spin-orbit effects in the near-zone metric and precession equations of compact binaries
• Searching for Gravitational Waves from Compact Binaries with Precessing Spins
• Revisiting a fundamental test of the disc instability model for X-ray binaries
• A Swift survey of accretion onto stellar-mass black holes
• Next-to-leading tail-induced spin-orbit effects in the gravitational radiation flux of compact binaries
• The Low-Spin Black Hole in LMC X-3
• A Systematic View of Ten New Black Hole Spins
• A Super-Eddington Compton-Thick Wind in GRO J1655-40?
• Black Hole Spin in X-ray Binaries: Giving Uncertainties an $f$
• The Case for a Low Mass Black Hole in the Low Mass X-ray Binary V1408 Aquilae (= 4U 1957+115)
• The Galactic LMXB Population and the Galactic Centre Region
• Results of the Swift Monitoring Campaign of the X-ray Binary 4U 1957+11: Constraints on Binary Parameters
• Evidence for an Evolving Cyclotron Line Energy in 4U 1538-522
• The stringent upper limit on jet power in the persistent soft state source 4U~1957+11
• IGR J17451-3022: a dipping and eclipsing low mass X-ray binary
• The Polarization of X-rays from Warped Black Hole Accretion Disks
• NICER/NuSTAR Characterization of 4U 1957+11: A Near Maximally Spinning Black Hole Potentially in the Mass Gap
• A Machine Learning Approach For Classifying Low-mass X-ray Binaries Based On Their Compact Object Nature
• Eclipses of jets and discs of X-ray binaries as a powerful tool for understanding jet physics and binary parameters
• Simultaneous optical and near-IR photometry of 4U 1957+115 - a missing secondary star
• Accretion Disc Evolution in GRO J1655-40 and LMC X-3 with Relativistic and Non-Relativistic Disc Models
• X-ray Polarization from Black Holes: GEMS Scientific White Paper
• The population of NuSTAR Black Hole X-ray Binaries
• Leveraging High Resolution Spectra to Understand Black Hole Spectra
• Spectral characteristics of the black hole binary 4U 1957+115: A multi-mission perspective
• Accretion Geometry of Black Hole X-ray Binaries: Insights from X-ray Observations
• Broad-band spectral study of LMXB black hole candidate 4U 1957+11 with NuSTAR