The population of faint X-ray sources in the galaxy and their contribution to the galactic ridge X-ray emission

2001 ◽  
Author(s):  
M. Sugizaki
Keyword(s):  
X Ray ◽  
The Galaxy

scholarly journals The role of AGN activity in the building up of the BCG at z ∼ 1.6

2019 ◽  
Vol 15 (S356) ◽  
pp. 280-284
Author(s):  
Angela Bongiorno ◽  
Andrea Travascio
Keyword(s):  
Galaxy Cluster ◽  
Cluster Galaxy ◽  
X Ray ◽  
Groups Of Galaxies ◽  
Star Forming ◽  
The Core ◽  
The Galaxy ◽  
Multi Wavelength

AbstractXDCPJ0044.0-2033 is one of the most massive galaxy cluster at z ∼1.6, for which a wealth of multi-wavelength photometric and spectroscopic data have been collected during the last years. I have reported on the properties of the galaxy members in the very central region (∼ 70kpc × 70kpc) of the cluster, derived through deep HST photometry, SINFONI and KMOS IFU spectroscopy, together with Chandra X-ray, ALMA and JVLA radio data.In the core of the cluster, we have identified two groups of galaxies (Complex A and Complex B), seven of them confirmed to be cluster members, with signatures of ongoing merging. These galaxies show perturbed morphologies and, three of them show signs of AGN activity. In particular, two of them, located at the center of each complex, have been found to host luminous, obscured and highly accreting AGN (λ = 0.4−0.6) exhibiting broad Hα line. Moreover, a third optically obscured type-2 AGN, has been discovered through BPT diagram in Complex A. The AGN at the center of Complex B is detected in X-ray while the other two, and their companions, are spatially related to radio emission. The three AGN provide one of the closest AGN triple at z > 1 revealed so far with a minimum (maximum) projected distance of 10 kpc (40 kpc). The discovery of multiple AGN activity in a highly star-forming region associated to the crowded core of a galaxy cluster at z ∼ 1.6, suggests that these processes have a key role in shaping the nascent Brightest Cluster Galaxy, observed at the center of local clusters. According to our data, all galaxies in the core of XDCPJ0044.0-2033 could form a BCG of M* ∼ 1012Mȯ hosting a BH of 2 × 108−109Mȯ, in a time scale of the order of 2.5 Gyrs.

Supermassive Black Hole feedback in early type galaxies

2020 ◽  
Vol 15 (S359) ◽  
pp. 119-125
Author(s):  
W. Forman ◽  
C. Jones ◽  
A. Bogdan ◽  
R. Kraft ◽  
E. Churazov ◽  
...  
Keyword(s):  
Dark Matter Halo ◽  
Scaling Relations ◽  
Radio Sources ◽  
Early Type ◽  
X Ray ◽  
Galaxy Groups ◽  
Sufficient Energy ◽  
The Galaxy ◽  
Simple Scaling ◽  
Halo Masses

AbstractOptically luminous early type galaxies host X-ray luminous, hot atmospheres. These hot atmospheres, which we refer to as coronae, undergo the same cooling and feedback processes as are commonly found in their more massive cousins, the gas rich atmospheres of galaxy groups and galaxy clusters. In particular, the hot coronae around galaxies radiatively cool and show cavities in X-ray images that are filled with relativistic plasma originating from jets powered by supermassive black holes (SMBH) at the galaxy centers. We discuss the SMBH feedback using an X-ray survey of early type galaxies carried out using Chandra X-ray Observatory observations. Early type galaxies with coronae very commonly have weak X-ray active nuclei and have associated radio sources. Based on the enthalpy of observed cavities in the coronae, there is sufficient energy to “balance” the observed radiative cooling. There are a very few remarkable examples of optically faint galaxies that are 1) unusually X-ray luminous, 2) have large dark matter halo masses, and 3) have large SMBHs (e.g., NGC4342 and NGC4291). These properties suggest that, in some galaxies, star formation may have been truncated at early times, breaking the simple scaling relations.

scholarly journals NuSTAR and Chandra Observations of New X-Ray Transients in the Central Parsec of the Galaxy

2019 ◽  
Vol 885 (2) ◽  
pp. 142 ◽  
Author(s):  
Kaya Mori ◽  
Charles J. Hailey ◽  
Shifra Mandel ◽  
Yve E. Schutt ◽  
Matteo Bachetti ◽  
...  
Keyword(s):  
X Ray ◽  
The Galaxy ◽  
Central Parsec

scholarly journals Anisotropy of the galaxy cluster X-ray luminosity–temperature relation

2018 ◽  
Vol 611 ◽  
pp. A50 ◽  
Author(s):  
Konstantinos Migkas ◽  
Thomas H. Reiprich
Keyword(s):  
Galaxy Clusters ◽  
Statistical Significance ◽  
Cosmological Parameters ◽  
Galaxy Cluster ◽  
Luminosity Distance ◽  
Temperature Relation ◽  
X Ray ◽  
Two Samples ◽  
The Galaxy ◽  
Group A

We introduce a new test to study the cosmological principle with galaxy clusters. Galaxy clusters exhibit a tight correlation between the luminosity and temperature of the X-ray-emitting intracluster medium. While the luminosity measurement depends on cosmological parameters through the luminosity distance, the temperature determination is cosmology-independent. We exploit this property to test the isotropy of the luminosity distance over the full extragalactic sky, through the normalization a of the LX–T scaling relation and the cosmological parameters Ωm and H0. To this end, we use two almost independent galaxy cluster samples: the ASCA Cluster Catalog (ACC) and the XMM Cluster Survey (XCS-DR1). Interestingly enough, these two samples appear to have the same pattern for a with respect to the Galactic longitude. More specifically, we identify one sky region within l ~ (−15°, 90°) (Group A) that shares very different best-fit values for the normalization of the LX–T relation for both ACC and XCS-DR1 samples. We use the Bootstrap and Jackknife methods to assess the statistical significance of these results. We find the deviation of Group A, compared to the rest of the sky in terms of a, to be ~2.7σ for ACC and ~3.1σ for XCS-DR1. This tension is not significantly relieved after excluding possible outliers and is not attributed to different redshift (z), temperature (T), or distributions of observable uncertainties. Moreover, a redshift conversion to the cosmic microwave background (CMB) frame does not have an important impact on our results. Using also the HIFLUGCS sample, we show that a possible excess of cool-core clusters in this region, is not able to explain the obtained deviations. Furthermore, we tested for a dependence of the results on supercluster environment, where the fraction of disturbed clusters might be enhanced, possibly affecting the LX–T relation. We indeed find a trend in the XCS-DR1 sample for supercluster members to be underluminous compared to field clusters. However, the fraction of supercluster members is similar in the different sky regions, so this cannot explain the observed differences, either. Constraining Ωm and H0 via the redshift evolution of LX–T and the luminosity distance via the flux–luminosity conversion, we obtain approximately the same deviation amplitudes as for a. It is interesting that the general observed behavior of Ωm for the sky regions that coincide with the CMB dipole is similar to what was found with other cosmological probes such as supernovae Ia. The reason for this behavior remains to be identified.

scholarly journals X-Ray Nova Flares

1975 ◽  
Vol 67 ◽  
pp. 501-508
Author(s):  
P. R. Amnuel ◽  
O. H. Guseinov
Keyword(s):  
Light Curve ◽  
Physical Nature ◽  
Dwarf Star ◽  
Optical Identification ◽  
X Ray ◽  
Spectral Class ◽  
Maximum Value ◽  
The Galaxy

In order to find out the physical nature of galactic X-ray sources, data on the variability of 24 sources during 1964–1971 have been investigated. The fluxes of 9 sources are found to be increasing to the maximum value (for several months) and then slowly decreasing (for 3 years). These 9 sources have been related by us to the class of X-ray Novae. The X-ray Nova synthetic light curve has been drawn from data of the fluxes of 9 discovered Novae. Assumptions have been made on the physical nature of the X-ray Novae. Between the flares the X-ray Novae may be weak X-ray sources with a luminosity of about 1034 erg s−1. During the flares the luminosity increases to about 1038 erg s−1. The number of X-ray sources in the Galaxy is about 103–104. The object of the optical identification may be a dwarf star of no earlier spectral class than F.

scholarly journals Radio and X-ray Observations of the Restarted Radio Galaxy in the Galaxy Cluster CL 0838+1948

Galaxies ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 108
Author(s):  
Simona Giacintucci ◽  
Tracy Clarke ◽  
Namir E. Kassim ◽  
Wendy Peters ◽  
Emil Polisensky
Keyword(s):  
Radio Source ◽  
Survey Data ◽  
Radio Galaxy ◽  
Galaxy Cluster ◽  
Gas Emission ◽  
Low Frequencies ◽  
Nuclear Activity ◽  
X Ray ◽  
Hot Gas ◽  
The Galaxy

We present VLA Low-band Ionosphere and Transient Experiment (VLITE) 338 MHz observations of the galaxy cluster CL 0838+1948. We combine the VLITE data with Giant Metrewave Radio Telescope 610 MHz observations and survey data. The central galaxy hosts a 250 kpc source whose emission is dominated by two large lobes at low frequencies. At higher frequencies, a pair of smaller lobes (∼30 kpc) is detected within the galaxy optical envelope. The observed morphology is consistent with a restarted radio galaxy. The outer lobes have a spectral index αout=1.6, indicating that they are old, whereas the inner lobes have αinn=0.6, typical for an active source. Spectral modeling confirms that the outer emission is a dying source whose nuclear activity switched off not more than 110 Myr ago. Using archival Chandra X-ray data, we compare the radio and hot gas emission. We find that the active radio source is contained within the innermost and X-ray brightest region, possibly a galactic corona. Alternatively, it could be the remnant of a larger cool core whose outer layers have been heated by the former epoch of activity that has generated the outer lobes.

Symbiotic X-ray binaries systems in the galaxy

2015 ◽  
Vol 41 (3-4) ◽  
pp. 114-127 ◽  
Author(s):  
A. G. Kuranov ◽  
K. A. Postnov
Keyword(s):  
X Ray ◽  
The Galaxy ◽  
X Ray Binaries

scholarly journals Spectroscopy of Stellar X-ray Sources in the Magellanic Clouds

1984 ◽  
Vol 108 ◽  
pp. 305-312
Author(s):  
J. B. Hutchings
Keyword(s):  
Black Hole ◽  
Magellanic Cloud ◽  
Active Galaxies ◽  
Magellanic Clouds ◽  
Dwarf Stars ◽  
X Ray ◽  
Preliminary Comparison ◽  
The Galaxy ◽  
Optical Identifications ◽  
X Ray Binaries

In the Magellanic Clouds, about 75 candidate stellar X-ray sources have been detected. Most of these positions have now been investigated and optical identifications made for ~ 50%. The majority of sources are foreground dwarf stars or background active galaxies. Detailed investigations exist for 3 SMC sources and 6 LMC sources. It is possible to make a preliminary comparison with the population of galactic X-ray sources. The Magellanic Cloud X-ray binaries have a number of unique or remarkable properties and the most important ones are presented and discussed. These include the most rapid pulsars (SMC X-1, 0538–66), the possible precessing disk in LMC X-4, and the black hole candidates LMC X-3, LMC X-1. The properties of these objects relate to the evolution of stars in the Magellanic Clouds and how it differs from the Galaxy.

scholarly journals An unusual transient following the short GRB 071227

2019 ◽  
Vol 489 (1) ◽  
pp. 13-27
Author(s):  
R A J Eyles ◽  
P T O’Brien ◽  
K Wiersema ◽  
R L C Starling ◽  
B P Gompertz ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Thermal Emission ◽  
Chemical Properties ◽  
Major Axis ◽  
Optical Observations ◽  
X Ray ◽  
Very Large Telescope ◽  
The Galaxy ◽  
Simple Extrapolation ◽  
Emission Models

ABSTRACT We present X-ray and optical observations of the short duration gamma-ray burst GRB 071227 and its host at z = 0.381, obtained using Swift, Gemini South, and the Very Large Telescope. We identify a short-lived and moderately bright optical transient, with flux significantly in excess of that expected from a simple extrapolation of the X-ray spectrum at 0.2–0.3 d after burst. We fit the SED with afterglow models allowing for high extinction and thermal emission models that approximate a kilonova to assess the excess’ origins. While some kilonova contribution is plausible, it is not favoured due to the low temperature and high luminosity required, implying superluminal expansion and a large ejecta mass of ∼0.1 M$\odot$. We find, instead, that the transient is broadly consistent with power-law spectra with additional dust extinction of E(B − V) ∼ 0.4 mag, although a possibly thermal excess remains in the z band. We investigate the host, a spiral galaxy with an edge-on orientation, resolving its spectrum along its major axis to construct the galaxy rotation curve and analyse the star formation and chemical properties. The integrated host emission shows evidence for high extinction, consistent with the afterglow findings. The metallicity and extinction are consistent with previous studies of this host and indicate the galaxy is a typical, but dusty, late-type SGRB host.

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