129 citations · 1.1k across the 38 of their papers we have counts for
39 papers
Cross-spectral Analysis of the Type-C Quasi-periodic Oscillation Shoulder Component in GX 339-4
Haifan Zhu, Mariano Méndez, Pengcheng Yang +8
We revisit Rossi X-ray Timing Explorer (RXTE) observations of GX~3394 during the rising phase of its 2006/2007 outburst and apply a joint power-density-spectrum (PDS)--cross-spe…
Geometry of the comptonization region of MAXI J1348630 through type-C quasi-periodic oscillations with NICER
Kevin Alabarta, Mariano Méndez, Federico García +5
We use the rms and lag spectra of the type-C quasi-periodic oscillation (QPO) to study the properties of the Comptonisation region (aka corona) during the low/hard and hard-interme…
Studies on the soft intermediate state X-ray flare of MAXI J1535-571 during its 2017 outburst
Ruican Ma, Lian Tao, Mariano Méndez +15
We analyzed an observation with the Nuclear Spectroscopic Telescope Array of the black-hole X-ray binary MAXI J1535-571 in the soft intermediate state, in which we detected a 2.5-k…
A systematic study of the high-frequency bump in the black-hole low-mass X-ray binary GX 339-4
Yuexin Zhang, Mariano Méndez, Sara E. Motta +8
The high-frequency bump, characterized by a frequency exceeding ~30 Hz, represents a seldom-explored time-variability feature in the power density spectrum (PDS) of black-hole X-ra…
Type-A quasi-periodic oscillation in the black hole transient MAXI J1348-630
Liang Zhang, Mariano Méndez, Federico García +12
We present a detailed analysis of the spectral and timing characteristics of a 7-Hz type-A quasi-periodic oscillation (QPO) detected in NICER observations of the black hole X-ray b…
A variable corona during the transition from type-C to type-B quasi-periodic oscillations in the black hole X-ray binary MAXI J1820+070
Ruican Ma, Mariano Mendez, Federico Garcia +3
We analyze a Neutron Star Interior Composition Explorer (NICER) observation of the black hole X-ray binary MAXI J1820+070 during a transition from type-C to type-B quasi-periodic o…
The mHz quasi-regular modulations of 4U 1630--47 during its 1998 outburst
Qingchang Zhao, Hongxing Yin, Lian Tao +19
We present the results of a detailed timing and spectral analysis of the quasi-regular modulation (QRM) phenomenon in the black hole X-ray binary 4U 1630--47 during its 1998 outbur…
QPOML: A Machine Learning Approach to Detect and Characterize Quasi-Periodic Oscillations in X-ray Binaries
Thaddaeus J. Kiker, James F. Steiner, Cecilia Garraffo +2
Astronomy is presently experiencing profound growth in the deployment of machine learning to explore large datasets. However, transient quasi-periodic oscillations (QPOs) which app…
Hilbert-Huang Transform analysis of quasi-periodic oscillations in MAXI J1820+070
Wei Yu, Qing-Cui Bu, Zi-Xu Yang +14
We present time-frequency analysis, based on the Hilbert-Huang transform (HHT), of the evolution on the low-frequency quasi-periodic oscillations (LFQPOs) observed in the black hol…
A spectral-timing study of the inner flow geometry in MAXI J1535--571 with -HXMT and NICER
Wei Yu, Qing-Cui Bu, He-Xin Liu +48
We have performed a spectral-timing analysis on the black hole X-ray binary MAXI J1535--571 during its 2017 outburst, with the aim of exploring the evolution of the inner accretion…
Fast transitions of X-ray variability in the black hole transient GX 339--4: comparison with MAXI J1820+070 and MAXI J1348-630
Zi-Xu Yang, Liang Zhang, S. N. Zhang +30
Fast transitions between different types of power density spectra (PDS) happening over timescales of several tens of seconds are rare phenomena in black hole X-ray binaries. In thi…
A NICER look at the jet-like corona of MAXI J1535-571 through type-B quasi-periodic oscillations
Yuexin Zhang, Mariano Méndez, Federico García +7
MAXI J1535-571 is a black-hole X-ray binary that in 2017 exhibited a very bright outburst which reached a peak flux of up to 5 Crab in the 2-20 keV band. Given the high flux, sever…
The comptonizing medium of the black-hole X-ray binary MAXI~J1535571 through type-C quasi-periodic oscillations
Divya Rawat, Mariano Méndez, Federico García +7
We present a detailed spectral and temporal analysis of the black-hole candidate MAXI~J1535571 using NICER observations in September and October 2017. We focus specifically on o…
Distribution of gamma-ray bursts on the t90-hardness ratio plane and their classification revisited
Liang Zhang, Juan-Juan Luo, Yong-Feng Huang +2
Using four mixed bivariate distributions (Normal distribution, Skew-Normal distribution, Student distribution, Skew-Student distribution) and bootstrap re-sampling analysis, we ana…
A possible 250-second X-ray quasi-periodicity in the fast blue optical transient AT2018cow
Wenjie Zhang, Xinwen Shu, Jin-Hong Chen +11
The fast blue optical transients (FBOTs) are a new population of extragalactic transients of unclear physical origin. A variety of mechanisms have been proposed including failed su…
High energy Millihertz quasi-periodic oscillations in 1A 0535+262 with Insight-HXMT challenge current models
Ruican Ma, Lian Tao, Shuang-Nan Zhang +21
We studied the millihertz quasi-periodic oscillation (mHz QPO) in the 2020 outburst of the Be/X-ray binary 1A 0535+262 using Insight-HXMT data over a broad energy band. The mHz QPO…
An Insight-HXMT view of the mHz quasi-regular modulation phenomenon in the black hole X-ray binary 4U 1630-47
Zi-Xu Yang, Liang Zhang, Yue Huang +97
Here we report the spectral-timing results of the black hole X-ray binary 4U 1630-47 during its 2021 outburst using observations from the Hard X-ray Modulation Telescope. Type-C qu…
Determination of QPO properties in the presence of strong broad-band noise: a case study on the data of MAXI J1820+070
Deng-Ke Zhou, Shuang-Nan Zhang, Li-Ming Song +8
Accurate calculation of the phase lags of quasi-periodic oscillations (QPOs) will provide insight into their origin. In this paper we investigate the phase lag correction method wh…
Variability and phase lags of the type-C quasi-periodic oscillation of MAXI J1348-630 with NICER
Kevin Alabarta, Mariano Méndez, Federico García +4
We study the properties of the type-C quasi-periodic oscillation (type-C QPO) of MAXI J1348-630 during its 2019 outburst and reflare with NICER. This is the first time that the evo…
The evolving properties of the corona of GRS 1915+105: A spectral-timing perspective through variable-Comptonisation modelling
Federico García, Konstantinos Karpouzas, Mariano Méndez +4
The inverse Compton process by which soft photons are up-scattered by hot electrons in a corona plays a fundamental role in shaping the X-ray spectra of black-hole (BH) low-mass X-…
The evolution of the high-frequency variability in the black hole candidate GRS 1915+105 as seen by RXTE
Yuexin Zhang, Mariano Méndez, Federico García +5
GRS 1915+105 can show type-C quasi-periodic oscillations (QPOs) in the power density spectrum. A high-frequency QPO (HFQPO) at 67 Hz has been observed in this source, albeit less o…
The accretion flow geometry of MAXI J1820+070 through broadband noise research with Insight-HXMT
Zi-Xu Yang, Liang Zhang, Qing-Cui Bu +24
Here we present a detailed study of the broadband noise in the power density spectra of the black hole X-ray binary MAXI J1820+070 during the hard state of its 2018 outburst, using…
Twin extreme ultraviolet waves in the solar corona
Ruisheng Zheng, Bing Wang, Liang Zhang +2
Solar extreme ultraviolet (EUV) waves are spectacular propagating disturbances with EUV enhancements in annular shapes in the solar corona. These EUV waves carry critical informati…
The evolution of the corona in MAXI J1535-571 through type-C quasi-periodic oscillations with Insight-HXMT
Yuexin Zhang, Mariano Méndez, Federico García +14
Type-C quasi-periodic oscillations (QPOs) in black hole X-ray transients can appear when the source is in the low-hard and hard-intermediate states. The spectral-timing evolution o…