126 research outputs found
Multiwavelength appearance of Vela Jr.: Is it up to expectations?
Vela Jr. is one of the youngest and likely nearest among the known galactic
supernova remnants (SNRs). Discovered in 1997 it has been studied since then at
quite a few wavelengths, that spread over almost 20 decades in energy. Here we
present and discuss Vela Jr. properties revealed by these multiwavelength
observations, and confront them with the SNR model expectations. Questions that
remained unanswered at the time of publication of the paper of Iyudin et al.
(2005), e.g. what is the nature of the SNR's proposed central compact source
CXOU J085201.4-461753, and why is the ISM absorption column density apparently
associated with RX J0852.0-4622 much greater than the typical column of the
Vela SNR, can be addressed using the latest radio and X-ray observations of
Vela Jr.. These, and other related questions are addressed in the following.Comment: 8 pages, 7 figures. Accepted for publication in ESA SP-622,
Proceedings of the 6th INTEGRAL Workshop held in Moscow, Russia, July 02-08,
200
Extended sources in the XMM-Newton slew survey
The low background, good spatial resolution and great sensitivity of the
EPIC-pn camera on XMM-Newton give useful limits for the detection of extended
sources even during the short exposures made during slewing maneouvers. In this
paper we attempt to illustrate the potential of the XMM-Newton slew survey as a
tool for analysing flux-limited samples of clusters of galaxies and other
sources of spatially extended X-ray emission.Comment: 2 pages, 4 figures, to appear in the proceedings of "The X-ray
Universe 2005", San Lorenzo de El Escorial (Spain), 26-30 September 200
The XMM-Newton Slew Survey: towards the XMMSL1 catalogue
The XMM-Newton satellite is the most sensitive X-ray observatory flown to
date due to the great collecting area of its mirrors coupled with the high
quantum efficiency of the EPIC detectors. It performs slewing manoeuvers
between observation targets tracking almost circular orbits through the
ecliptic poles due to the Sun constraint. Slews are made with the EPIC cameras
open and the other instruments closed, operating with the observing mode set to
the one of the previous pointed observation and the medium filter in place.
Slew observations from the EPIC-pn camera in FF, eFF and LW modes provide
data, resulting in a maximum of 15 seconds of on-source time. These data can be
used to give a uniform survey of the X-ray sky, at great sensitivity in the
hard band compared with other X-ray all-sky surveys.Comment: 2 pages, 2 figures, to appear in the proceedings of "The X-ray
Universe 2005", San Lorenzo de El Escorial (Spain), 26-30 September 200
The XMM-Newton Slew Survey: a wide-angle survey in the 0.2 - 12 keV band
The scientific data collected during slews of the XMM-Newton satellite are
used to construct a slew survey catalogue. This comprises of the order of 4000
sources detected in the EPIC-pn 0.2-12 keV band with exposures of less than 15s
and a sky coverage of about 6300 square degrees (source density ~0.65 per
square degree). Below 2 keV the sensitivity limit is comparable to the ROSAT
PSPC All-Sky Survey and the XMM-Newton slew survey offers long-term variablity
studies. Above 2 keV the survey will be a factor of 10 more sensitive than all
previous all-sky X-ray surveys. The slew survey is almost complementary to the
serendipitous survey compiled from pointed XMM-Newton observations. It is aimed
to release the first source catalogue by the end of 2005. Later slew
observations and detections will continuously be added. This paper discusses
the XMM-Newton slew survey also in a historical context.Comment: 6 pages, 6 figures, to appear in the proceedings of "The X-ray
Universe 2005", San Lorenzo de El Escorial (Spain), 26-30 September 200
Mechanisms of amphetamine action illuminated through optical monitoring of dopamine synaptic vesicles in Drosophila brain
Amphetamines elevate extracellular dopamine, but the underlying mechanisms remain uncertain. Here we show in rodents that acute pharmacological inhibition of the vesicular monoamine transporter (VMAT) blocks amphetamine-induced locomotion and self-administration without impacting cocaine-induced behaviours. To study VMATâs role in mediating amphetamine action in dopamine neurons, we have used novel genetic, pharmacological and optical approaches in Drosophila melanogaster. In an ex vivo whole-brain preparation, fluorescent reporters of vesicular cargo and of vesicular pH reveal that amphetamine redistributes vesicle contents and diminishes the vesicle pH-gradient responsible for dopamine uptake and retention. This amphetamine-induced deacidification requires VMAT function and results from net H+ antiport by VMAT out of the vesicle lumen coupled to inward amphetamine transport. Amphetamine-induced vesicle deacidification also requires functional dopamine transporter (DAT) at the plasma membrane. Thus, we find that at pharmacologically relevant concentrations, amphetamines must be actively transported by DAT and VMAT in tandem to produce psychostimulant effects
X-ray studies of the Abell 3158 galaxy cluster with eROSITA
Context. The most nearby clusters are the best places for studying physical and enrichment effects in the faint cluster outskirts. The Abell 3158 cluster (A3158), located at z = 0.059, is quite extended with a characteristic radius r = 23.95 arcmin. The metal distribution in the outskirts of this cluster has previously been studied with XMM-Newton. In 2019, A3158 was observed as a calibration target in a pointed observation with the eROSITA telescope on board the Spektrum-Roentgen-Gamma mission. Bright large clusters, such as A3158, are ideal for studying the metal distribution in the cluster outskirts, along with the temperature profile and morphology. With the deeper observation time of the eROSITA telescope, these properties can now be studied in greater detail and at larger radii. Furthermore, bright nearby clusters are ideal X-ray instrumental cross-calibration targets as they cover a large fraction of the detector and do not vary in time.
Aims. We first compare the temperature, metal abundance, and normalisation profiles of the cluster from eROSITA with previous XMM-Newton and Chandra data. Following this calibration work, we investigate the temperature and metallicity of the cluster out to almost r, measure the galaxy velocity dispersion, and determine the cluster mass. Furthermore, we search for infalling clumps and background clusters in the field.
Methods. We determined 1D temperature, abundance, and normalisation profiles from both eROSITA and XMM-Newton data as well as 2D maps of temperature and metal abundance distribution from eROSITA data. The velocity dispersion was determined and the cluster mass was calculated from the massâvelocity dispersion (MâÏ) relation. Galaxy density maps were created to enable a better understanding of the structure of the cluster and the outskirts.
Results. The overall (i.e. in the range 0.2â0.5r) temperature was measured to be 5.158 ± 0.038 keV. The temperature, abundance, and normalisation profiles of eROSITA all agree to within a confidence level of about 10% with those we determined using XMM-Newton and Chandra data, and they are also consistent with the profiles published previously by the X-COP project. The cluster morphology and surface brightness profile of cluster Abell 3158 appear to be regular at a first glance. Clusters that have such profiles typically are relaxed and host cool cores. However, the temperature profile and map show that the cluster lacks a cool core, as was noted before. Instead, an off-centre cool clump lies to the west of the central cluster region, as reported previously. These are indications that the cluster may be undergoing some sloshing and merger activity. Furthermore, there is a bow-shaped edge near the location of the cool gas clump west of the cluster centre. Farther out west of the X-ray images of A3158, an extension of gas is detected. This larger-scale extension is described here for the first time. The gas metallicity (~0.2 solar) measured in the outskirts (»r) is consistent with an early-enrichment scenario. The velocity dispersion of the cluster member galaxies is measured to be 1058 ± 41 kms based on spectroscopic redshifts of 365 cluster member galaxies and the total mass is determined as M,c = 1.38 ± 0.25 Ă 10 Mâ. The mass estimate based on the X-ray temperature is significantly lower at M200 = 6.20 ± 0.75 Ă 10 Mâ, providing further indications that merger activity boosts the velocity dispersion and/or biases the temperature low. An extended X-ray source located south of the field of view also coincides with a galaxy overdensity with spectroscopic redshifts in the range 0.05 < z < 0.07. This source further supports the idea that the cluster is undergoing merger activity. Another extended source located north of the field of view is detected in X-rays and coincides with an overdensity of galaxies with spectroscopic redshifts in the range of 0.070 < z < 0.077. This is likely a background cluster that is not directly related to A3158. Additionally, the known South Pole Telescope cluster SPT-CL J0342-5354 at z = 0. 53 was detected
X-Ray Studies of the Abell 3158 Galaxy Cluster with eROSITA
The most nearby clusters are the best places to study physical and enrichment
effects in the faint cluster outskirts. A3158 located at z=0.059 is quite
extended with a characteristic radius r=23.95 arcmin. In 2019, A3158
was observed as a calibration target in a pointed observation with the eROSITA
telescope onboard the SRG mission.
We determined 1d temperature, abundance and normalisation profiles from
eROSITA and XMM-Newton and Chandra data as well as 2d maps of temperature
distribution from eROSITA data. The velocity dispersion was determined and the
cluster mass was calculated.
The overall temperature was measured to be 4.725 0.035 keV. The profiles
of eROSITA all agree on a ~10% level with those determined with XMM-Newton and
Chandra data. From the temperature map we see that the cluster lacks a cool
core, as noted before. The presence of a previously detected off-centre cool
clump West of the central cluster region is observed. Furthermore there is a
bow shaped edge near the location of the cool gas clump West of the cluster
centre. An extension of gas is detected for the first time further out in the
West. The velocity dispersion of the cluster was measured to be 105841 km
s. The total mass was determined as =1.38 0.25x10
. The mass estimate from the M-T relation is significantly lower at
M=5.09 0.59x10. An extended X-ray source located
South of the cluster also coincides with a galaxy overdensity with redshifts in
the range 0.05<z<0.07. These are indications that the cluster may be undergoing
merger activity. Another extended source located North of the cluster is
detected in X-rays and coincides with an overdensity of galaxies with redshifts
in the range of 0.070<z<0.077. This is likely a background cluster not related
to A3158. Additionally a known SPT cluster at z=0.53 was detected.Comment: 14 pages, 17 figures in the main text, and 3 figures in the appendix.
Accepted by A&A for the Special Issue: The Early Data Release of eROSITA and
Mikhail Pavlinsky ART-XC on the SRG Missio
Gewalt in der Schule
Vortrag auf der Tagung Bindung, Trauma und soziale Gewalt , 3.-5.12.2004 in Frankfurt am Main
The Abell 3391/95 galaxy cluster system:A 15 Mpc intergalactic medium emission filament, a warm gas bridge, infalling matter clumps, and (re-) accelerated plasma discovered by combining SRG/eROSITA data with ASKAP/EMU and DECam data
We used dedicated SRG/eROSITA X-ray, ASKAP/EMU radio, and DECam optical
observations of a 15 sq.deg region around the interacting galaxy cluster system
A3391/95 to study the warm-hot gas in cluster outskirts and filaments, the
surrounding large-scale structure and its formation process. We relate the
observations to expectations from cosmological hydrodynamic simulations from
the Magneticum suite.
We trace the irregular morphology of warm-hot gas of the main clusters from
their centers out to well beyond their characteristic radii, . Between
the two main cluster systems, we observe an emission bridge; thanks to
eROSITA's unique soft response and large field of view, we discover tantalizing
hints for warm gas. Several matter clumps physically surrounding the system are
detected. For the "Northern Clump," we provide evidence that it is falling
towards A3391 from the hot gas morphology and radio lobe structure of its
central AGN. Many of the extended sources in the field detected by eROSITA are
known clusters or new clusters in the background, including a known SZ cluster
at redshift z=1. We discover an emission filament north of the virial radius,
, of A3391 connecting to the Northern Clump and extending south of
A3395 towards another galaxy cluster. The total projected length of this
continuous warm-hot emission filament is 15 Mpc, running almost 4 degrees
across the entire eROSITA observation. The DECam galaxy density map shows
galaxy overdensities in the same regions. The new datasets provide impressive
confirmation of the theoretically expected structure formation processes on the
individual system level, including the surrounding warm-hot intergalactic
medium distribution compared to the Magneticum simulation. Our spatially
resolved findings show that baryons indeed reside in large-scale warm-hot gas
filaments with a clumpy structure.Comment: 21 pages plus 16 figures in the main text and 13 pages plus 29
figures as appendix. Astronomy & Astrophysics, accepted on November 3, 2020.
A press release, full resolution images plus additional images and movies are
available at https://astro.uni-bonn.de/~reiprich/A3391_95
The eROSITA X-ray telescope on SRG
eROSITA (extended ROentgen Survey with an Imaging Telescope Array) is the primary instrument on the Spectrum-Roentgen-Gamma (SRG) mission, which was successfully launched on July 13, 2019, from the Baikonour cosmodrome. After the commissioning of the instrument and a subsequent calibration and performance verification phase, eROSITA started a survey of the entire sky on December 13, 2019. By the end of 2023, eight complete scans of the celestial sphere will have been performed, each lasting six months. At the end of this program, the eROSITA all-sky survey in the soft X-ray band (0.2-2.3 keV) will be about 25 times more sensitive than the ROSAT All-Sky Survey, while in the hard band (2.3-8 keV) it will provide the first ever true imaging survey of the sky. The eROSITA design driving science is the detection of large samples of galaxy clusters up to redshifts z > 1 in order to study the large-scale structure of the universe and test cosmological models including Dark Energy. In addition, eROSITA is expected to yield a sample of a few million AGNs, including obscured objects, revolutionizing our view of the evolution of supermassive black holes. The survey will also provide new insights into a wide range of astrophysical phenomena, including X-ray binaries, active stars, and diffuse emission within the Galaxy. Results from early observations, some of which are presented here, confirm that the performance of the instrument is able to fulfil its scientific promise. With this paper, we aim to give a concise description of the instrument, its performance as measured on ground, its operation in space, and also the first results from in-orbit measurements
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