We report on Chandra X-ray Observatory (CXO) High-Energy Transmission Grating (HETG) spectra of the dipping Low Mass X-ray Binary (LMXB) 1A 1744-361 during its July 2008 outburst. We find that its persistent emission is well modeled by a blackbody (kT ~ 1.0 keV) plus power-law ($Γ$ ~ 1.7) with an absorption edge at 7.6 keV. In the residuals of the combined spectrum we find a significant absorption line at 6.961+/-0.002 keV, consistent with the Fe XXVI (hydrogen-like Fe) 2 - 1 transition. We place an upper limit on the velocity of a redshifted flow of v < 221 km/s. We find an equivalent width for the line of 27^+2_-3 eV, from which we determine a column density of 7+/-1x10^17 cm^-2 via a curve-of-growth analysis. Using XSTAR simulations, we place a lower limit on the ionization parameter of > 10^3.6 erg cm/s. The properties of this line are consistent with those observed in other dipping LMXBs. Using Rossi X-ray Timing Explorer (RXTE) data accumulated during this latest outburst we present an updated color-color diagram which clearly shows that 1A 1744-361 is an "atoll" source. Finally, using additional dips found in the RXTE and CXO data we provide an updated orbital period estimate of 52+/-5 minutes.
Context: XB 1916-053 is a low mass X-ray binary system (LMXB) hosting a neutron star (NS) and showing periodic dips. The spectrum of the persistent emission was modeled with a blackbody component having a temperature between 1.31 and 1.67 keV and with a Comptonization component with an electron temperature of 9.4 keV and a photon index $Γ$ between 2.5 and 2.9. The presence of absorption features associated with highly ionized elements suggested the presence of partially ionized plasma in the system. Aims: In this work we performed a study of the spectrum of XB 1916-053, which aims to shed ligh…
Joint XMM-Newton and NuSTAR Observations of Type I X-ray Bursts from the Dipping Low-Mass X-ray Binary 4U 1323-62
Istanbul University（伊斯坦布尔大学）；Sabancı University（萨班吉大学）；University of Southampton（南安普顿大学）；University of Amsterdam（阿姆斯特丹大学）；Georgia Institute of Technology（佐治亚理工学院）
The bright, erratic black hole X-ray binary GRS 1915+105 has long been a target for studies of disk instabilities, radio/infrared jets, and accretion disk winds, with implications that often apply to sources that do not exhibit its exotic X-ray variability. With the launch of NICER, we have a new opportunity to study the disk wind in GRS 1915+105 and its variability on short and long timescales. Here we present our analysis of 39 NICER observations of GRS 1915+105 collected during five months of the mission data validation and verification phase, focusing on Fe XXV and Fe XXVI absorption. We r…
XB 1254-690 is a dipping low mass X-ray binary system hosting a neutron star and showing type I X-ray bursts. We aim at obtaining more accurate orbital ephemeris and at constraining the orbital period derivative of the system for the first time. In addition, we want to better constrain the distance to the source in order to locate the system in a well defined evolutive scenario. We apply for the first time an orbital timing technique to XB 1254-690, using the arrival times of the dips present in the light curves that have been collected during 26 years of X-ray pointed observations performed f…
The very small accretion disks in ultra-compact X-ray binaries (UCXBs) are special laboratories in which to study disk accretion and outflows. We report on three sets of new (250 ks total) and archival (50 ks) Chandra/HETG observations of the "dipping" neutron-star X-ray binary 4U 1916$-$053, which has an orbital period of $P\simeq 50$~minutes. We find that the bulk of the absorption in all three spectra originates in a disk atmosphere that is redshifted by $v\simeq 220-290$ $\text{km}$ $\text{s}^{-1}$, corresponding to the gravitational redshift at radius of $R \sim 1200$ $GM/{c}^{2}$. This s…
Utilizing an archived Suzaku data acquired on 2007 December 25 for 46 ks, X-ray spectroscopic properties of the dipping and eclipsing low-mass X-ray binary EXO 0748$-$676 were studied. At an assumed distance of 7.1 kpc, the data gave a persistent unabsorbed luminosity of $3.4\times10^{36}$ erg cm$^{-2}$ s$^{-1}$ in 0.6 $-$ 55 keV. The source was in a relatively bright low/hard state, wherein the 0.6 $-$ 55 keV spectrum can be successfully explained by a "double-seed" Comptonization model, incorporating a common corona with an electron temperature of $\sim13$ keV. The seed photons are thought t…
4U 1624-490 as a possible intermediate-mass X-ray binary: constraints from XRISM and NuSTAR spectroscopy
Università degli Studi di Palermo（巴勒莫大学）；Osservatorio Astronomico di Cagliari, Istituto nazionale di astrofisica（卡利亚里天文台，意大利国家天体物理研究所）；INAF – IASF Palermo（意大利国家天体物理研究所帕勒莫天文空间物理研究所）；INAF – Osservatorio Astronomica di Brera（意大利国家天体物理研究所布雷拉天文台）
We report the first detection of highly ionized Fe species in the X-ray spectrum of the eclipsing and dipping Low Mass X-ray Binary XTE J1710-281. Using archival Chandra and Suzaku observations, we have carried out a spectro-timing analysis of the source during three different epochs. We compare the average orbital profile and obtain differences in pre-eclipse dip morphologies between different observation epochs. We observe an orbit to orbit evolution of the dips for the first time in this source in both the Chandra observations, reflecting changes in the structure of the accretion disc in ti…
The dipping source XB 1916-053 is a compact binary system with an orbital period of 50 min harboring a neutron star. Using ten new {\it Chandra} observations and one {\it Swift/XRT} observation, we are able to extend the baseline of the orbital ephemeris; this allows us to exclude some models that explain the dip arrival times. The Chandra observations provide a good plasma diagnostic of the ionized absorber and allow us to determine whether it is placed at the outer rim of the accretion disk or closer to the compact object. From the available observations we are able to obtain three new dip a…
X-ray and Radio Monitoring of the Neutron Star Low Mass X-ray Binary 1A 1744-361: Quasi Periodic Oscillations, Transient Ejections, and a Disk Atmosphere
通过对中子星低质量X射线双星1A 1744-361为期三个月的X射线与射电监测，首次发现约8 Hz准周期振荡，证实其在爆发峰值呈现Z态特征，并观测到 atoll 态下 island 到 banana 态转变时的瞬态喷流抛射及吸积盘大气吸收线。
A highly ionised outflow in the X-ray binary 4U 1624-49 detected with XRISM
ESO（欧洲南方天文台）；SRON Netherlands Institute for Space Research（荷兰空间研究所）；Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA)（日本宇宙航空研究开发机构宇宙科学研究所）；Faculty of Science and Technology, Tokyo University of Science（东京理科大学理工学部）；Department of Physics, Ehime University（爱媛大学理学部物理学科）；Villanova University（维拉诺瓦大学）；NASA/Goddard Space Flight Center（美国国家航空航天局戈达德太空飞行中心）；Center for Research and Exploration in Space Science and Technology, NASA/GSFC (CRESST II)（NASA/GSFC空间科学与技术研究探索中心）；Center for Space Science and Technology, University of Maryland, Baltimore County (UMBC)（马里兰大学巴尔的摩县分校空间科学与技术中心）；Department of Astronomy, University of Michigan（密歇根大学天文学系）
XRISM finds the Changing-Look AGN NGC 1365 in an extended low state: A dense, highly ionized outflow obscures the central source
Massachusetts Institute of Technology（麻省理工学院）；Harvard & Smithsonian（哈佛-史密森尼天体物理中心）；Technion（以色列理工学院）；University of Maryland（马里兰大学）；Eureka Scientific, Inc.（尤里卡科学公司）；California Institute of Technology（加州理工学院）
XRISM Resolve Spectroscopy of GX 5-1: Constraints on Iron Spectral Features in a Luminous Neutron-Star Binary
RIKEN Nishina Center for Accelerator-Based Science（理化学研究所仁科加速器科学中心）；Department of Physics, Rikkyo University（立教大学物理学系）；Department of Physics, Kyoto University（京都大学物理学系）；Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA)（日本宇宙航空研究开发机构太空科学研究所）
利用 XRISM Resolve 对 Z 源 GX 5-1 进行高分辨率光谱观测，未发现显著铁谱线，给出等效宽度上限，证实其连续谱主导特性。
