scholarly journals Confirmed short periodic variability of subparsec supermassive binary black hole candidate Mrk 231

2020 ◽  
Vol 494 (3) ◽  
pp. 4069-4076 ◽  
Author(s):  
Andjelka B Kovačević ◽  
Tignfeng Yi ◽  
Xinyu Dai ◽  
Xing Yang ◽  
Iva Čvorović-Hajdinjak ◽  
...  
Keyword(s):  
Black Hole ◽  
Equal Mass ◽  
Optical Data ◽  
Mass Ratio ◽  
Data Set ◽  
Black Hole Candidate ◽  
Limited Sampling ◽  
Binary Black Hole ◽  
Low Mass ◽  
Significant Periodicity

ABSTRACT Here we confirm the short periodic variability of a subparsec supermassive binary black hole (SMBBH) candidate Mrk 231 in the extended optical photometric data set collected by the Catalina Real-Time Transient Survey (CRTS) and All-Sky Automated Survey for Supernovae (ASAS-SN). Using the Lomb–Scargle periodogram and 2DHybrid method, we detected the significant periodicity of ∼1.1 yr beyond a damped random walk model in the CRTS+ASAS-SN optical data set. Mrk 231 has been previously proposed as an SMBBH candidate with a highly unequal mass ratio (q ∼ 0.03), very tight mutual separation of ∼590 au, and an orbital period of ∼1.2 yr. Hence, our result further supports, even though not prove, the intriguing hypothesis that SMBBHs with low mass ratios may be more common than close-equal mass SMBBHs. This result, however, was obtained from the contribution of the CRTS data with limited sampling cadence and photometric accuracy, and further monitoring of Mrk 231 is crucial to confirm the periodicity.

scholarly journals A black hole X-ray binary at ∼100 Hz: multiwavelength timing of MAXI J1820+070 with HiPERCAM and NICER

2019 ◽  
Vol 490 (1) ◽  
pp. L62-L66 ◽  
Author(s):  
J A Paice ◽  
P Gandhi ◽  
T Shahbaz ◽  
P Uttley ◽  
Z Arzoumanian ◽  
...  
Keyword(s):  
Black Hole ◽  
Time Scales ◽  
X Rays ◽  
X Ray ◽  
Black Hole Candidate ◽  
Optical Wavelength ◽  
The Third ◽  
Binary Black Hole ◽  
Internal Shock ◽  
Low Mass

ABSTRACT We report on simultaneous sub-second optical and X-ray timing observations of the low-mass X-ray binary black hole candidate MAXI J1820+070. The bright 2018 outburst rise allowed simultaneous photometry in five optical bands (ugrizs) with HiPERCAM/GTC (Optical) at frame rates over 100 Hz, together with NICER/ISS observations (X-rays). Intense (factor of 2) red flaring activity in the optical is seen over a broad range of time-scales down to ∼10 ms. Cross-correlating the bands reveals a prominent anticorrelation on time-scales of ∼seconds, and a narrow sub-second correlation at a lag of ≈ +165 ms (optical lagging X-rays). This lag increases with optical wavelength, and is approximately constant over Fourier frequencies of ∼0.3–10 Hz. These features are consistent with an origin in the inner accretion flow and jet base within ∼5000 Gravitational radii. An additional ∼+5 s lag feature may be ascribable to disc reprocessing. MAXI J1820+070 is the third black hole transient to display a clear ∼0.1 s optical lag, which may be common feature in such objects. The sub-second lag variation with wavelength is novel, and may allow constraints on internal shock jet stratification models.

scholarly journals Forming bulges during galaxy minor mergers

2007 ◽  
Vol 3 (S245) ◽  
pp. 63-66 ◽  
Author(s):  
T. J. Cox ◽  
J. Younger ◽  
L. Hernquist ◽  
P. F. Hopkins
Keyword(s):  
Black Hole ◽  
Large Mass ◽  
Elliptical Galaxies ◽  
Equal Mass ◽  
Mass Ratio ◽  
Black Hole Growth ◽  
Major Merger ◽  
Hole Growth ◽  
Minor Mergers ◽  
Large Mass Ratio

AbstractThe hierarchical formation of structure suggests that dark halos, and the galaxies they host, are shaped by their merging history. While the idea that mergers between galaxies of equal mass, i.e., major merger, produce elliptical galaxies has received considerable attention, he galaxies that result from minor merger, i.e., mergers between galaxies with a large mass ratio, is much less understood. We have performed a large number of numerical simulations of minor mergers, including cooling, star formation, and black hole growth in order to study this process in more detail. This talk will present some preliminary results of this study, and in particular, the morphology and kinematics of minor merger remnants.

The BL Lac PG 1553+113: a supermassive binary black hole candidate

2019 ◽  
Vol 30 (S1) ◽  
pp. 145-148
Author(s):  
Pere Munar-Adrover ◽  
Marco Tavani ◽  
Alfonso Cavaliere ◽  
Andrea Argan
Keyword(s):  
Black Hole ◽  
Black Hole Candidate ◽  
Binary Black Hole ◽  
Bl Lac

scholarly journals FIRST LONG-TERM OPTICAL SPECTRAL MONITORING OF A BINARY BLACK HOLE CANDIDATE E1821+643. I. VARIABILITY OF SPECTRAL LINES AND CONTINUUM

2016 ◽  
Vol 222 (2) ◽  
pp. 25 ◽  
Author(s):  
A. I. Shapovalova ◽  
L. Č. Popović ◽  
V. H. Chavushyan ◽  
A. N. Burenkov ◽  
D. Ilić ◽  
...  
Keyword(s):  
Black Hole ◽  
Spectral Lines ◽  
Black Hole Candidate ◽  
Binary Black Hole ◽  
Spectral Monitoring

scholarly journals The MAVERIC survey: a hidden pulsar and a black hole candidate in ATCA radio imaging of the globular cluster NGC 6397

2020 ◽  
Vol 493 (4) ◽  
pp. 6033-6049 ◽  
Author(s):  
Yue Zhao ◽  
Craig O Heinke ◽  
Vlad Tudor ◽  
Arash Bahramian ◽  
James C A Miller-Jones ◽  
...  
Keyword(s):  
Black Hole ◽  
Globular Cluster ◽  
Radio Observation ◽  
Millisecond Pulsar ◽  
Radio Flux ◽  
X Ray ◽  
Black Hole Candidate ◽  
Radio Imaging ◽  
Low Mass ◽  
Compact Array

ABSTRACT Using a 16.2-h radio observation by the Australia Telescope Compact Array and archival Chandra data, we found >5σ radio counterparts to four known and three new X-ray sources within the half-light radius (rh) of the Galactic globular cluster NGC 6397. The previously suggested millisecond pulsar (MSP) candidate, U18, is a steep-spectrum (Sν ∝ να; $\alpha =-2.0^{+0.4}_{-0.5}$) radio source with a 5.5-GHz flux density of 54.7 ± 4.3 $\mu \mathrm{ Jy}$. We argue that U18 is most likely a ‘hidden’ MSP that is continuously hidden by plasma shocked at the collision between the winds from the pulsar and companion star. The non-detection of radio pulsations so far is probably the result of enhanced scattering in this shocked wind. On the other hand, we observed the 5.5-GHz flux of the known MSP PSR J1740−5340 (U12) to decrease by a factor of >2.8 during epochs of 1.4-GHz eclipse, indicating that the radio flux is absorbed in its shocked wind. If U18 is indeed a pulsar whose pulsations are scattered, we note the contrast with U12’s flux decreases in eclipse, which argues for two different eclipse mechanisms at the same radio frequency. In addition to U12 and U18, we also found radio associations for five other Chandra X-ray sources, four of which are likely background galaxies. The last, U97, which shows strong H α variability, is mysterious; it may be either a quiescent black hole low-mass X-ray binary or something more unusual.

scholarly journals Optical Photometry of LMXBs: UW CrB (=MS 1603+260) and V1408 Aql (=4U 1957+115)

2015 ◽  
Vol 2 (1) ◽  
pp. 50-54
Author(s):  
P. A. Mason ◽  
E. L. Robinson ◽  
S. Gomez ◽  
J. V. Segura
Keyword(s):  
Black Hole ◽  
Orbital Period ◽  
Light Curves ◽  
Optical Data ◽  
Published Data ◽  
Type I ◽  
Optical Photometry ◽  
Mean Intensity ◽  
X Ray ◽  
Low Mass

We present new optical observations of V1408 Aql (= 4U 1957+115), the only low mass X-ray binary, black hole candidate known to be in a persistently soft state. We combine new broadband optical photometry with previously published data and derive a precise orbital ephemeris. The optical light curves display sinusoidal variations modulated on the orbital period as well as large night to night changes in mean intensity. The amplitude of the variations increases with mean intensity while maintaining sinusoidal shape. Considering the set of constraints placed by the X-ray and optical data we argue that V1408 Aql may harbor a very low mass black hole. Optical light curves of UW CrB display partial eclipses of the accretion disk by the donor star that vary both in depth and orbital phase. The new eclipses of UW CrB in conjunction with published eclipse timings are well fitted with a linear ephemeris. We derive an upper limit to the rate of change of the orbital period. By including the newly observed type I bursts with published bursts in our analysis, we find that optical bursts are not observed between orbital phases 0.93 and 0.07, i.e. they are not observable during partial eclipses of the disk.

scholarly journals Disc and wind in black hole X-ray binary MAXI J1820+070 observed through polarized light during its 2018 outburst

2020 ◽  
Vol 496 (1) ◽  
pp. L96-L100
Author(s):  
Ilia A Kosenkov ◽  
Alexandra Veledina ◽  
Andrei V Berdyugin ◽  
Vadim Kravtsov ◽  
Vilppu Piirola ◽  
...  
Keyword(s):  
Black Hole ◽  
Polarized Light ◽  
Position Angle ◽  
Intrinsic Polarization ◽  
Data Set ◽  
X Ray ◽  
Soft State ◽  
Hard State ◽  
Low Mass ◽  
Optical Flux

ABSTRACT We describe the first complete polarimetric data set of the entire outburst of a low-mass black hole X-ray binary system and discuss the constraints for geometry and radiative mechanisms it imposes. During the decaying hard state, when the optical flux is dominated by the non-thermal component, the observed polarization is consistent with the interstellar values in all filters. During the soft state, the intrinsic polarization of the source is small, ∼0.15 per cent in B and V filters, and is likely produced in the irradiated disc. A much higher polarization, reaching ∼0.5 per cent in V and R filters, at a position angle of ∼25○ observed in the rising hard state coincides in time with the detection of winds in the system. This angle coincides with the position angle of the jet. The detected optical polarization is best explained by scattering of the non-thermal (hot flow or jet base) radiation in an equatorial wind.

Sign in / Sign up

Export Citation Format

Share Document