scholarly journals The Close AGN Reference Survey (CARS)

2018 ◽  
Vol 618 ◽  
pp. A27 ◽  
Author(s):  
M. C. Powell ◽  
B. Husemann ◽  
G. R. Tremblay ◽  
M. Krumpe ◽  
T. Urrutia ◽  
...  
Keyword(s):  
Ambient Medium ◽  
Theoretical Models ◽  
Ionized Gas ◽  
X Ray ◽  
Gas Streams ◽  
Hot Gas ◽  
Upper Limits ◽  
Theoretical Predictions ◽  
Different Origins

Aims. We probe the radiatively-efficient, hot wind feedback mode in two nearby luminous unobscured (type 1) AGN from the Close AGN Reference Survey (CARS), which show intriguing kpc-scale arc-like features of extended [O III]ionized gas as mapped with VLT-MUSE. We aimed to detect hot gas bubbles that would indicate the existence of powerful, galaxy-scale outflows in our targets, HE 0227–0931 and HE 0351+0240, from deep (200 ks) Chandra observations. Methods. By measuring the spatial and spectral properties of the extended X-ray emission and comparing with the sub kpc-scale IFU data, we are able to constrain feedback scenarios and directly test if the ionized gas is due to a shocked wind. Results. No extended hot gas emission on kpc-scales was detected. Unless the ambient medium density is low (n H  ∼  1 cm−3 at 100 pc), the inferred upper limits on the extended X-ray luminosities are well below what is expected from theoretical models at matching AGN luminosities. Conclusions. We conclude that the highly-ionized gas structures on kpc scales are not inflated by a hot outflow in either target, and instead are likely caused by photoionization of pre-existing gas streams of different origins. Our nondetections suggest that extended X-ray emission from an AGN-driven wind is not universal, and may lead to conflicts with current theoretical predictions.

scholarly journals Hot gaseous atmospheres of rotating galaxies observed with XMM–Newton

2020 ◽  
Vol 499 (4) ◽  
pp. 5163-5174
Author(s):  
A Juráňová ◽  
N Werner ◽  
P E J Nulsen ◽  
M Gaspari ◽  
K Lakhchaura ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Active Galactic Nuclei ◽  
Spiral Galaxy ◽  
Galactic Nuclei ◽  
X Ray ◽  
Hot Gas ◽  
Heating And Cooling ◽  
Theoretical Predictions ◽  
Central Regions ◽  
Gaseous Atmospheres

ABSTRACT X-ray emitting atmospheres of non-rotating early-type galaxies and their connection to central active galactic nuclei have been thoroughly studied over the years. However, in systems with significant angular momentum, processes of heating and cooling are likely to proceed differently. We present an analysis of the hot atmospheres of six lenticulars and a spiral galaxy to study the effects of angular momentum on the hot gas properties. We find an alignment between the hot gas and the stellar distribution, with the ellipticity of the X-ray emission generally lower than that of the optical stellar emission, consistent with theoretical predictions for rotationally supported hot atmospheres. The entropy profiles of NGC 4382 and the massive spiral galaxy NGC 1961 are significantly shallower than the entropy distribution in other galaxies, suggesting the presence of strong heating (via outflows or compressional) in the central regions of these systems. Finally, we investigate the thermal (in)stability of the hot atmospheres via criteria such as the TI- and C-ratio, and discuss the possibility that the discs of cold gas present in these objects have condensed out of the hot atmospheres.

scholarly journals Chandra X-ray Observations of Dwarf Starburst Galaxies

2004 ◽  
Vol 217 ◽  
pp. 304-309
Author(s):  
Jürgen Ott ◽  
Fabian Walter ◽  
Elias Brinks ◽  
Ulrich Klein
Keyword(s):  
Interstellar Medium ◽  
Gravitational Potential ◽  
Thermal Plasma ◽  
Theoretical Models ◽  
Starburst Galaxies ◽  
Host Galaxy ◽  
X Ray ◽  
Hot Gas ◽  
Neutral Gas

We obtained X-ray observations for a sample of eight nearby dwarf starburst galaxies from the Chandra X-ray Observatory. Five galaxies of our sample show extended (size: 1-10 kpc), diffuse X-ray emission which can be attributed to a hot thermal plasma. This phase of the interstellar medium purportedly drives the expansion of supergiant shells. A comparison of the derived gas parameters with theoretical models reveals that the hot gas in principle is capable to escape from the gravitational potential of the host galaxy. However, the outflows appear to be contained in those cases where an extended envelope or massive tidal features of neutral gas exist.

scholarly journals Constraints from LIGO O3 Data on Gravitational-wave Emission Due to R-modes in the Glitching Pulsar PSR J0537–6910

2021 ◽  
Vol 922 (1) ◽  
pp. 71
Author(s):  
R. Abbott ◽  
T. D. Abbott ◽  
S. Abraham ◽  
F. Acernese ◽  
K. Ackley ◽  
...  
Keyword(s):  
Energy Conservation ◽  
Gravitational Wave ◽  
Gravitational Waves ◽  
Theoretical Models ◽  
X Ray ◽  
Spin Evolution ◽  
Upper Limits ◽  
Wave Emission ◽  
Using Data

Abstract We present a search for continuous gravitational-wave emission due to r-modes in the pulsar PSR J0537–6910 using data from the LIGO–Virgo Collaboration observing run O3. PSR J0537–6910 is a young energetic X-ray pulsar and is the most frequent glitcher known. The inter-glitch braking index of the pulsar suggests that gravitational-wave emission due to r-mode oscillations may play an important role in the spin evolution of this pulsar. Theoretical models confirm this possibility and predict emission at a level that can be probed by ground-based detectors. In order to explore this scenario, we search for r-mode emission in the epochs between glitches by using a contemporaneous timing ephemeris obtained from NICER data. We do not detect any signals in the theoretically expected band of 86–97 Hz, and report upper limits on the amplitude of the gravitational waves. Our results improve on previous amplitude upper limits from r-modes in J0537-6910 by a factor of up to 3 and place stringent constraints on theoretical models for r-mode-driven spin-down in PSR J0537–6910, especially for higher frequencies at which our results reach below the spin-down limit defined by energy conservation.

scholarly journals The Nature of the Dusty Ionized Gas in NGC 5846: (And Other Elliptical Galaxies ?)

1999 ◽  
Vol 186 ◽  
pp. 199-199
Author(s):  
Paul Goudfrooij ◽  
Ginevra Trinchieri
Keyword(s):  
Elliptical Galaxy ◽  
Elliptical Galaxies ◽  
Ionized Gas ◽  
Full Account ◽  
Optical Extinction ◽  
X Ray ◽  
Cooling Flow ◽  
Hot Gas ◽  
Optical Imagery ◽  
Astronomy And Astrophysics

We present new optical imagery and ROSAT HRI X-ray imagery of the elliptical galaxy NGC 5846. A filamentary dust lane is detected in its central region, with a morphology strikingly similar to that observed for the optical nebulosity and the X-ray emission (cf. Fig. 1). A physical connection between the different phases of the interstellar medium therefore seems likely. The energy deposited from the hot gas into heating of the dust grains is consistent with the temperature distribution of the X-ray-emitting gas, which is found to be lowest in the dusty regions. The optical extinction of the dust is consistent with the Galactic extinction curve. We argue that the dust as well as the optical nebulosity are products of an interaction with a small, gas-rich galaxy, not remnants of a cooling flow. A full account of this work is currently in press in Astronomy and Astrophysics, and a preprint is available through http://www.stsci.edu/science/preprints/prep1191/prep1191.html.

scholarly journals Limits on the optical magnitude of PSR 1821-24 in M28

2000 ◽  
Vol 177 ◽  
pp. 313-314
Author(s):  
F. K. Sutaria
Keyword(s):  
Energy Loss ◽  
Theoretical Models ◽  
Rotational Energy ◽  
Pulsar Emission ◽  
X Ray ◽  
V Band ◽  
Upper Limits ◽  
Optical Limit ◽  
Multiwavelength Observations

AbstractThe detection of a pulsed X-ray counterpart (RX J1824.2-2R52P) of the 3.05 ms pulsar PSR 1821-24, suggests the possibility of a part of the rotational energy loss of this high spindown rate pulsar being in the optical band. Archival HST data for M28 is used here to set upper limits on the optical V-band magnitude of PSR 1821-24. The optical limit extends the multiwavelength observations for this source and provides a constraint for theoretical models of pulsar emission.

scholarly journals Feedback of massive stars on the ISM: a XMM-Newton view of the LMC superbubble N 51D

2003 ◽  
Vol 212 ◽  
pp. 637-641 ◽  
Author(s):  
Dominik J. Bomans ◽  
Jörn Rossa ◽  
Kerstin Weis ◽  
Konrad Dennerl
Keyword(s):  
Surface Brightness ◽  
Massive Stars ◽  
Radial Expansion ◽  
Type Ii ◽  
Ionized Gas ◽  
Abundance Pattern ◽  
X Ray ◽  
Hot Gas ◽  
Galactic Winds

N 51D (= DEM L 192) appears at first glance as a nearly circular, 120 pc diameter bubble of ionized gas around the LMC OB association LH 54. A deeper look reveals a complex web of filaments and deviations from radial expansion. Using a deep XMM-Newton pointing centered on N 51D we find that diffuse soft X-ray emitting gas fills the whole superbubble as delineated by the Hα filaments. Contrary to recent findings for galactic winds, the correlation between Hα and X-ray surface brightness is not good. The X-ray spectrum of this diffuse gas cannot be fitted with the LMC abundance pattern, but implies an overabundance of at least oxygen and neon, consistent with recent enrichment from supernovae Type II. Some indications for enhanced mixing at the brightest region of the Hα shell and for a beginning outflow of the hot gas were also detected.

scholarly journals HERA Phase I Limits on the Cosmic 21 cm Signal: Constraints on Astrophysics and Cosmology during the Epoch of Reionization

2022 ◽  
Vol 924 (2) ◽  
pp. 51
Author(s):  
Zara Abdurashidova ◽  
James E. Aguirre ◽  
Paul Alexander ◽  
Zaki S. Ali ◽  
Yanga Balfour ◽  
...  
Keyword(s):  
Theoretical Models ◽  
Hydrogen Gas ◽  
X Rays ◽  
X Ray ◽  
Upper Limits ◽  
Adiabatic Cooling ◽  
Radio Background ◽  
Early Galaxies ◽  
First Galaxies ◽  
Low X

Abstract Recently, the Hydrogen Epoch of Reionization Array (HERA) has produced the experiment’s first upper limits on the power spectrum of 21 cm fluctuations at z ∼ 8 and 10. Here, we use several independent theoretical models to infer constraints on the intergalactic medium (IGM) and galaxies during the epoch of reionization from these limits. We find that the IGM must have been heated above the adiabatic-cooling threshold by z ∼ 8, independent of uncertainties about IGM ionization and the radio background. Combining HERA limits with complementary observations constrains the spin temperature of the z ∼ 8 neutral IGM to 27 K 〈 T ¯ S 〉 630 K (2.3 K 〈 T ¯ S 〉 640 K) at 68% (95%) confidence. They therefore also place a lower bound on X-ray heating, a previously unconstrained aspects of early galaxies. For example, if the cosmic microwave background dominates the z ∼ 8 radio background, the new HERA limits imply that the first galaxies produced X-rays more efficiently than local ones. The z ∼ 10 limits require even earlier heating if dark-matter interactions cool the hydrogen gas. If an extra radio background is produced by galaxies, we rule out (at 95% confidence) the combination of high radio and low X-ray luminosities of L r,ν /SFR > 4 × 1024 W Hz−1 M ⊙ − 1 yr and L X /SFR < 7.6 × 1039 erg s−1 M ⊙ − 1 yr. The new HERA upper limits neither support nor disfavor a cosmological interpretation of the recent Experiment to Detect the Global EOR Signature (EDGES) measurement. The framework described here provides a foundation for the interpretation of future HERA results.

scholarly journals x-cigale: fitting AGN/galaxy SEDs from X-ray to infrared

2019 ◽  
Vol 491 (1) ◽  
pp. 740-757 ◽  
Author(s):  
G Yang(杨光) ◽  
M Boquien ◽  
V Buat ◽  
D Burgarella ◽  
L Ciesla ◽  
...  
Keyword(s):  
Spectral Energy Distribution ◽  
Source Code ◽  
Spectral Energy ◽  
Model Parameters ◽  
Current Version ◽  
Two Phase ◽  
X Ray ◽  
Dust Extinction ◽  
Upper Limits

ABSTRACT Code Investigating GALaxy Emission (cigale) is a powerful multiwavelength spectral energy distribution (SED) fitting code for extragalactic studies. However, the current version of cigale is not able to fit X-ray data, which often provide unique insights into active galactic nucleus (AGN) intrinsic power. We develop a new X-ray module for cigale, allowing it to fit SEDs from the X-ray to infrared (IR). We also improve the AGN fitting of cigale from UV-to-IR wavelengths. We implement a modern clumpy two-phase torus model, skirtor. To account for moderately extincted type 1 AGNs, we implement polar-dust extinction. We publicly release the source code (named ‘x-cigale’). We test x-cigale with X-ray detected AGNs in SDSS, COSMOS, and AKARI-NEP. The fitting quality (as indicated by reduced χ2) is good in general, indicating that x-cigale is capable of modelling the observed SED from X-ray to IR. We discuss constrainability and degeneracy of model parameters in the fitting of AKARI-NEP, for which excellent mid-IR photometric coverage is available. We also test fitting a sample of AKARI-NEP galaxies for which only X-ray upper limits are available from Chandra observations, and find that the upper limit can effectively constrain the AGN SED contribution for some systems. Finally, using x-cigale, we assess the ability of Athena to constrain the AGN activity in future extragalactic studies.

scholarly journals A search for very high-energy flares from the microquasars GRS 1915+105, Circinus X-1, and V4641 Sgr using contemporaneous H.E.S.S. and RXTE observations

2018 ◽  
Vol 612 ◽  
pp. A10 ◽  
Author(s):  
◽  
H. Abdalla ◽  
A. Abramowski ◽  
F. Aharonian ◽  
F. Ait Benkhali ◽  
...  
Keyword(s):  
Theoretical Models ◽  
High Energy ◽  
Photon Flux ◽  
Telescope Array ◽  
X Ray ◽  
Cherenkov Telescope ◽  
Intrinsic Absorption ◽  
Upper Limits ◽  
Very High Energy ◽  
Very High

Context. Microquasars are potential γ-ray emitters. Indications of transient episodes of γ-ray emission were recently reported in at least two systems: Cyg X-1 and Cyg X-3. The identification of additional γ-ray-emitting microquasars is required to better understand how γ-ray emission can be produced in these systems.Aim. Theoretical models have predicted very high-energy (VHE) γ-ray emission from microquasars during periods of transient outburst. Observations reported herein were undertaken with the objective of observing a broadband flaring event in the γ-ray and X-ray bands.Methods. Contemporaneous observations of three microquasars, GRS 1915+105, Circinus X-1, and V4641 Sgr, were obtained using the High Energy Spectroscopic System (H.E.S.S.) telescope array and the Rossi X-ray Timing Explorer (RXTE) satellite. X-ray analyses for each microquasar were performed and VHE γ-ray upper limits from contemporaneous H.E.S.S. observations were derived.Results. No significant γ-ray signal has been detected in any of the three systems. The integral γ-ray photon flux at the observational epochs is constrained to be I(>560 GeV) < 7.3 × 10−13 cm−2 s−1, I(>560 GeV ) < 1.2 × 10−12 cm−2 s−1, and I(>240 GeV) < 4.5 × 10−12 cm−2 s−1 for GRS 1915+105, Circinus X-1, and V4641 Sgr, respectively.Conclusions. The γ-ray upper limits obtained using H.E.S.S. are examined in the context of previous Cherenkov telescope observations of microquasars. The effect of intrinsic absorption is modelled for each target and found to have negligible impact on the flux of escaping γ-rays. When combined with the X-ray behaviour observed using RXTE, the derived results indicate that if detectable VHE γ-ray emission from microquasars is commonplace, then it is likely to be highly transient.

scholarly journals Candidates for Optical Counterpart in the Field of PSR 1821–24 in M28

2000 ◽  
Vol 195 ◽  
pp. 431-432
Author(s):  
F. K. Sutaria
Keyword(s):  
Theoretical Models ◽  
Radio Pulsar ◽  
Optical Counterpart ◽  
Pulsar Emission ◽  
X Ray ◽  
V Band ◽  
Upper Limits ◽  
Optical Limit ◽  
Multiwavelength Observations

The 3-ms, X-ray pulsar RX J1824.2-2R52P has been identified at the 2-σ level as a possible X-ray counterpart of the radio pulsar PSR 1821-24. The present work uses archival HST data for M28 to set upper limits on the optical V-band magnitude of PSR 1821–24 / RX J1824.2-2R452P. The optical limit extends the multiwavelength observations for this source and would provide constraints for theoretical models of pulsar emission.

Sign in / Sign up

Export Citation Format

Share Document