The field containing the candidate High Mass X-ray Binary IGR J01363+6610 was observed by XMM-Newton on 2009 July 31 for 28 ks. A Be star was previously suggested as the possible counterpart of the INTEGRAL source, and although Chandra, during a 2007 observation, did not detect an X-ray source at the position of the Be star, we find a variable source (XMMU J013549.5+661243) with an average X-ray flux of 2e-13 ergs/cm2/s (0.2-12 keV, unabsorbed) at this position with XMM-Newton. The spectrum of this source is consistent with a hard power-law with a photon index of 1.4 +/- 0.3 and a column density of 1.5e22 cm^-2 (90% confidence errors). These results, along with our optical investigation of other X-ray sources in the field, makes the association with the Be star very likely, and the 2 kpc distance estimate for the Be star indicates an X-ray luminosity of 9.1e31 ergs/s. This is lower than typical for a Be X-ray binary, and the upper limit on the luminosity was even lower (<1.4e31 ergs/s assuming the same spectral model) during the Chandra observation. We discuss possible implications of the very low quiescent luminosity for the physical properties of IGR J01363+6610.
In the work we present the results of two deep broad-band observations of the poorly studied X-ray pulsar IGR J19294+1816 obtained with the NuSTAR observatory. The source was observed during Type I outburst and in the quiescent state. In the bright state a cyclotron absorption line in the energy spectrum was discovered at $E_{\rm cyc}=42.8\pm0.7$ keV. Spectral and timing analysis prove the ongoing accretion also during the quiescent state of the source. Based on the long-term flux evolution, particularly on the transition of the source to the bright quiescent state with luminosity around $10^{…
Using X-ray observations from the NuSTAR and Swift satellites, we present temporal and spectral properties of an intermediate polar (IP) IGR J16547-1916. A persistent X-ray period at ~ 546 s confirming the optical spin period obtained from previous observations is detected. The detection of a strong X-ray spin pulse reinforces the classification of this system as an intermediate polar. The lack of orbital or side-band periodicities in the X-rays implies that the system is accreting predominantly via a disk. A variable covering absorber appears to be responsible for the spin pulsations in the l…
A FAST search for radio pulsations during the dormant state of the AMSPs IGR J00291+5934 and MAXI J1957+032
Institute of Space Sciences (ICE, CSIC)（空间科学研究所）；Institut d’Estudis Espacials de Catalunya (IEEC)（加泰罗尼亚太空研究学院）；Universidad de Santiago de Chile (USACH)（智利圣地亚哥大学）；Center for Interdisciplinary Research in Astrophysics and Space Sciences (CIRAS)（天体物理学与空间科学跨学科研究中心）；INAF/IASF Palermo（意大利国家天体物理研究所巴勒莫天文台）；Université Grenoble Alpes, CNRS, IPAG（格勒诺布尔阿尔卑斯大学）；INAF–Osservatorio Astronomico di Brera（意大利国家天体物理研究所布雷拉天文台）；INAF Osservatorio Astronomico di Roma（意大利国家天体物理研究所罗马天文台）；Università degli Studi di Cagliari（卡利亚里大学）
Detection of low-luminosity X-ray pulsations from the accreting millisecond pulsar IGR J17511-3057: An ever-thinning thread between bright accretion and sub-luminous states
INAF–Osservatorio Astronomico di Brera（意大利国家天体物理研究所布雷拉天文台）；INAF-Osservatorio Astronomico di Roma（意大利国家天体物理研究所罗马天文台）；Institute of Space Sciences (ICE, CSIC)（空间科学研究所（加泰罗尼亚高等研究理事会））；Institut d’Estudis Espacials de Catalunya (IEEC)（加泰罗尼亚空间研究院）；INAF, Istituto di Astrofisica Spaziale e Fisica Cosmica（意大利国家天体物理研究所空间天体物理与宇宙学研究所）；ASI - Agenzia Spaziale Italiana（意大利航天局）
We present time-resolved 10.4-m GTC and 4.2-m WHT intermediate resolution spectroscopy of the X-ray transient MAXI J1820+070 (=ASASSN-18ey) obtained during its decline to the quiescent state. Cross-correlation of the 21 individual spectra against late-type templates reveals a sinusoidal velocity modulation with a period of 0.68549 +/- 0.00001 d and semi-amplitude of 417.7 +/- 3.9 km/s. We derive a mass function f(M) = 5.18 +/- 0.15 Msun, dynamically confirming the black hole nature of the compact object. Our analysis of the stellar absorption features supports a K3-5 spectral classification fo…
We report on the results of an XMM-Newton observation of the Supergiant Fast X-ray Transient (SFXT) IGR J08408-4503 performed in June 2020. The source is composed by a compact object (likely a neutron star) orbiting around an O8.5Ib-II(f)p star, LM Vel. The X-ray light curve shows a very low level of emission, punctuated by a single, faint flare. Analysis of spectra measured during the flare and during quiescence is performed. The quiescent state shows a continuum spectrum well deconvolved to three spectral models: two components are from a collisionally-ionized plasma (with temperatures kT1=0…
The properties of the disk/jet coupling in quiescent black hole low mass X-ray binaries (BH LMXBs) are still largely unknown. In this paper we present the first quasi-simultaneous radio and X-ray detection in quiescence of the BH LMXB MAXI J1348$-$630, which is known to display a hybrid disk/jet connection that depends on the accretion rate. We performed deep X-ray and radio observations using the Chandra X-ray Observatory and the Australia Telescope Compact Array. MAXI J1348$-$630 is detected for the first time in quiescence at an X-ray luminosity $L_{\rm X} = (7.5 \pm 2.9) \times 10^{30} (D/…
