Collisional Plasma Models with APEC/APED: Emission-Line Diagnostics of Hydrogen-like and Helium-like Ions

Smith, Randall K.; Brickhouse, N. S.; Liedahl, D. A.; Raymond, J. C.

doi:10.1086/322992

Cited by 1,949 publications

(1,757 citation statements)

References 33 publications

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“…As noted in H06, the three unresolved CXB spectra (CDFN-VF, CDFN-F, and CDFS) in the 0.4-10 keV band are fit well by a simple model consisting of a power law absorbed by the Galactic hydrogen column (N H = 1.5×10 20 cm 2 for CDFN and 0.9×10 20 cm 2 for CDFS) representing the extragalactic component, plus unabsorbed local warm thermal emission with solar heavy element abundances (the APEC model [65]). We assumed the power law to be the same between the CDFN-VF and CDFN-F spectra, but allowed it to be different for CDFS, since it points to a different region of the sky.…”

Section: Chandra Cxb Spectrummentioning

confidence: 90%

Limits on the radiative decay of sterile neutrino dark matter from the unresolved cosmic and soft x-ray backgrounds

et al. 2007

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We present upper limits on line emission in the Cosmic X-ray background (CXB) that would be produced by decay of sterile neutrino dark matter. We employ the spectra of the unresolved component of the CXB in the Chandra Deep Fields North and South obtained with the Chandra CCD detector in the E = 0.8 − 9 keV band. The expected decay flux comes from the dark matter on the lines of sight through the Milky Way galactic halo. Our constraints on the sterile neutrino decay rate are sensitive to the modeling of the Milky Way halo. The highest halo mass estimates provide a limit on the sterile neutrino mass of ms < 2.9 keV in the Dodelson-Widrow production model, while the lowest halo mass estimates provide the conservative limit of ms < 5.7 keV (2σ). We also discuss constraints from a short observation of the softer (E < 1 keV) X-ray background with a rocket-borne calorimeter by McCammon and collaborators.

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Section: Chandra Cxb Spectrummentioning

confidence: 90%

Limits on the radiative decay of sterile neutrino dark matter from the unresolved cosmic and soft x-ray backgrounds

et al. 2007

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“…The instrumental background was subtracted from themand the sky background was modeled with the sum of an unabsorbed thermal component (APEC; Smith et al 2001) describing emission from the Local Hot Bubble (LHB), an absorbed thermal component describing emission from the Galactic Halo (GH), and an absorbed powerlaw component describing emission from unresolved point sources. We used photoelectric absorption cross-sections from Verner et al (1996)and the elemental abundances from Feldman (1992).…”

Section: Chandra Background Modelingmentioning

confidence: 99%

Chandra and JVLA Observations of HST Frontier Fields Cluster MACS J0717.5+3745

Weeren

Ogrean

Jones

et al. 2017

ApJ

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To investigate the relationship between thermal and non-thermal components in merger galaxy clusters, we present deep JVLA and Chandraobservations of the HST Frontier Fields cluster MACSJ0717.5+3745. The Chandraimage shows a complex merger event, with at least four components belonging to different merging subclusters. Northwestof the cluster, ∼0.7 Mpc from the center, there is a ram-pressure-stripped core that appears to have traversed the densest parts of the cluster after entering the intracluster medium (ICM) from the direction of a galaxy filament to the southeast. We detect a density discontinuity north-northeastof this core, which we speculate is associated with a cold front. Our radio images reveal new details for the complex radio relic and radio halo in this cluster. In addition, we discover several new filamentary radio sources with sizes of 100-300kpc. A few of these seem to be connected to the main radio relic, while others are either embedded within the radio halo or projected onto it. A narrow-angled-tailed (NAT) radio galaxy, a cluster member, is located at the center of the radio relic. The steep spectrum tails of this active galactic nucleuslead into the large radio relic where the radio spectrum flattens again. This morphological connection between the NAT radio galaxy and relic provides evidence for reacceleration (revival) of fossil electrons. The presence of hot 20 keV ICM gas detected by Chandranear the relic location provides additional support for this re-acceleration scenario.

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“…11, were best fitted with two temperature (2T) as- trophysical plasma model (apec; Smith et al, 2001), with variable elemental abundances (Z). The interstellar hydrogen column density (NH) was left free to vary.…”

Section: Coronal and Chromospheric Featuresmentioning

confidence: 99%

LO Peg: surface differential rotation, flares, and spot-topographic evolution

Karmakar

Pandey

Саванов

et al. 2016

Mon. Not. R. Astron. Soc.

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Using the wealth of ∼24 yr multiband data, we present an in-depth study of the starspot cycles, surface differential rotations (SDR), optical flares, evolution of star-spot distributions, and coronal activities on the surface of young, single, main-sequence, ultrafast rotator (UFR) LO Peg. From the long-term V -band photometry, we derive rotational period of LO Peg to be 0.4231 ± 0.0001 d. Using the seasonal variations on the rotational period, the SDR pattern is investigated, and shows a solar-like pattern of SDR. A cyclic pattern with period of ∼2.7 yr appears to be present in rotational period variation. During the observations, 20 optical flares are detected with a flare frequency of ∼1 flare per two days and with flare energy of ∼10 31−34 erg. The surface coverage of cool spots is found to be in the range of ∼9-26 per cent. It appears that the high-and low-latitude spots are interchanging their positions. Quasi-simultaneous observations in X-ray, UV, and optical photometric bands show a signature of an excess of X-ray and UV activities in spotted regions.

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Collisional Plasma Models with APEC/APED: Emission-Line Diagnostics of Hydrogen-like and Helium-like Ions

Cited by 1,949 publications

References 33 publications

Limits on the radiative decay of sterile neutrino dark matter from the unresolved cosmic and soft x-ray backgrounds

Limits on the radiative decay of sterile neutrino dark matter from the unresolved cosmic and soft x-ray backgrounds

Chandra and JVLA Observations of HST Frontier Fields Cluster MACS J0717.5+3745

LO Peg: surface differential rotation, flares, and spot-topographic evolution

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