Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userIdentification of High Mass X-ray Binaries selected from XMM-Newton observations of the LMC
111
0
0.0
(
0
)
Added by
Naomi van Jaarsveld
Publication date
2017
fields
Physics
and research's language is
English
Ask ChatGPT about the research
No Arabic abstract
The Large Magellanic Cloud (LMC) currently hosts around 23 high mass X-ray binaries (HMXBs) of which most are Be/X-ray binaries. The LMC XMM-Newton survey provided follow-up observations of previously known X-ray sources that were likely HMXBs, as well as identifying new HMXB candidates. In total 19 candidate HMXBs were selected based on their X-ray hardness ratios. In this paper we present red and blue optical spectroscopy, obtained with SALT and the SAAO 1.9-m telescope, plus a timing analysis of the long term optical light curves from OGLE to confirm the nature of these candidates. We find that 9 of the candidates are new Be/X-ray Binaries, substantially increasing the LMC Be/X-ray binary population. Furthermore, we present the optical properties of these new systems, both individually and as a group of all the BeXBs identified by the XMM-Newton survey of the LMC.
rate research
Read More
The study of X-ray reprocessing is one of the key diagnostic tools to probe the environment in X-ray binary systems. One difficult aspect of studying X-ray reprocessing is the presence of much brighter primary radiation from the compact star together with the reprocessed radiation. In contrast for eclipsing systems, the X-rays we receive during eclipse are only those produced by reprocessing of the emission from the compact star by the surrounding medium. We report results from a spectral study of the X-ray emission during eclipse and outside eclipse (when available) in 9 high mass X-ray binaries (HMXBs) with XMM- Newton EPIC pn to investigate different aspects of the stellar wind in these HMXBs. During eclipse the continuum component of the spectrum is reduced by a factor of $sim$8-237, but the count-rate for 6.4 keV Iron emission line or complex of Iron emission lines in HMXBs are reduced by a smaller factor leading to large equivalent widths of the Iron emission lines. This indicates a large size for the line emission region, comparable to or larger than the companion star in these HMXB systems. However there are significant system to system differences. 4U 1538$-$52, in spite of having a large absorption column density, shows a soft emission component with comparable flux during the eclipse and out-of-eclipse phases. Emission from Hydrogen-like Iron has been observed in LMC X-4 for the first time, in the out-of-eclipse phase in one of the observations. Overall, we find significant differences in the eclipse spectrum of different HMXBs and also in their eclipse spectra against out-of-eclipse spectra.
Since it started observing the sky, the INTEGRAL satellite has discovered new categories of high mass X-ray binaries (HMXB) in our Galaxy. These observations raise important questions on the formation and evolution of these rare and short-lived objects. We present here new infrared observations from which to reveal or constrain the nature of 15 INTEGRAL sources, which allow us to update and discuss the Galactic HMXB population statistics. After previous photometric and spectroscopic observing campaigns in the optical and near-infrared, new photometry and spectroscopy was performed in the near-infrared with the SofI instrument on the ESO/NTT telescope in 2008 and 2010 on a sample of INTEGRAL sources. These observations, and specifically the detection of certain features in the spectra, allow the identification of these high-energy objects by comparison with published nIR spectral atlases of O and B stars. We present photometric data of nine sources (IGR J10101-5654, IGR J11187-5438, IGR J11435-6109, IGR J14331-6112, IGR J16328-4726, IGR J17200-3116, IGR J17354-3255, IGR J17404-3655, and IGR J17586-2129) and spectroscopic observations of 13 sources (IGR J10101-5654, IGR J11435-6109, IGR J13020-6359, IGR J14331-6112, IGR J14488-5942, IGR J16195-4945, IGR J16318-4848, IGR J16320-4751, IGR J16328-4726, IGR J16418-4532, IGR J17354-3255, IGR J17404-3655, and IGR J17586-2129). Our spectroscopic measurements indicate that: five of these objects are Oe/Be high-mass X-ray binaries (BeHMXB), six are supergiant high-mass X-ray binaries (sgHMXB), and two are sgB[e]. From a statistical point of view, we estimate the proportion of confirmed sgHMXB to be 42% and that of the confirmed BeHMXB to be 49%. The remaining 9% are peculiar HMXB.
We present preliminary results on Herschel/PACS mid/far-infrared photometric observations of INTEGRAL supergiant High Mass X-ray Binaries (HMXBs), with the aim of detecting the presence and characterizing the nature of absorbing material (dust and/or cold gas), either enshrouding the whole binary systems, or surrounding the sources within their close environment. These unique observations allow us to better characterize the nature of these HMXBs, to constrain the link with their environment (impact and feedback), and finally to get a better understanding of the formation and evolution of such rare and short-living supergiant HMXBs in our Galaxy.
Context: Finding Active Galactic Nuclei (AGN) behind the Magellanic Clouds (MCs) is difficult because of the high stellar density in these fields. Although the first AGN behind the Small Magellanic Cloud (SMC) were reported in the 1980s, it is only recently that the number of AGN known behind the SMC has increased by several orders of magnitude. Aims: The mid-infrared colour selection technique has been proven to be an efficient means of identifying AGN, especially obscured sources. The X-ray regime is complementary in this regard and we use XMM-Newton observations to support the identification of AGN behind the SMC. Methods: We present a catalogue of AGN behind the SMC by correlating an updated X-ray point source catalogue from our XMM-Newton survey of the SMC with already known AGN from the literature as well as a list of candidates obtained from the ALLWISE mid-infrared colour selection criterion. We studied the properties of the sample with respect to their redshifts, luminosities and X-ray spectral characteristics. We also identified the near-infrared counterpart of the sources from the VISTA observations. Results: The redshift and luminosity distributions of the sample (where known) indicate that we detect sources from nearby Seyfert galaxies to distant and obscured quasars. The X-ray hardness ratios are compatible with those typically expected for AGN. The VISTA colours and variability are also consistent in this regard. A positive correlation was observed between the integrated X-ray flux (0.2--12 keV) and the ALLWISE and VISTA magnitudes. We further present a sample of new candidate AGN and candidates for obscured AGN. All of these make an interesting subset for further follow-up studies. An initial spectroscopic follow-up of 6 out of the 81 new candidates showed all six sources are active galaxies, albeit two with narrow emission lines.
We present the results of two XMM-Newton observations of Jupiter carried out in 2003 for 100 and 250 ks (or 3 and 7 planet rotations) respectively. X-ray images from the EPIC CCD cameras show prominent emission from the auroral regions in the 0.2 - 2.0 keV band: the spectra are well modelled by a combination of emission lines, including most prominently those of highly ionised oxygen (OVII and OVIII). In addition, and for the first time, XMM-Newton reveals the presence in both aurorae of a higher energy component (3 - 7 keV) which is well described by an electron bremsstrahlung spectrum. This component is found to be variable in flux and spectral shape during the Nov. 2003 observation, which corresponded to an extended period of intense solar activity. Emission from the equatorial regions of Jupiters disk is also observed, with a spectrum consistent with that of solar X-rays scattered in the planets upper atmosphere. Jupiters X-rays are spectrally resolved with the RGS which clearly separates the prominent OVII contribution of the aurorae from the OVIII, FeXVII and MgXI lines, originating in the low-latitude disk regions of the planet.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
