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101. Chandra X-ray Observatory Study of the Orion Nebula Cluster and BN/KL Region

Author

Garmire, Gordon, Feigelson, Eric D., Broos, Patrick, Hillenbrand, Lynne A., Pravdo, Steven H., Townsley, Leisa, and Tsuboi, Yohko

Subjects
Astrophysics
Abstract

About 1000 X-ray emitting young pre-main sequence (PMS) stars distributed in mass from 0.05 to 50 solar masses are detected in an image of the Orion Nebula obtained with the Advanced CCD Imaging Spectrometer on board the Chandra X-ray Observatory. This is the richest field of sources ever obtained in X-ray astronomy. ACIS sources include 85-90% of V<20 stars, plus a substantial fraction of deeply embedded stars with extinctions as high as A_V~60. The relationships between X-ray and other PMS stellar properties suggest that X-ray luminosity of lower-mass PMS stars depends more on mass, and possibly stellar rotation, than on bolometric luminosity as widely reported. A subsample of unabsorbed solar-mass stars show high X-ray luminosities around L_x ~ 2 x 10^30 erg/s for the first ~2 My but diverge during 2-10 My with X-ray emission plummeting in some stars but remaining high in others. This behavior is consistent with theories of stellar rotational history and magnetic dynamos. The Becklin-Neugebauer/Kleinman-Low (BN/KL) region of massive star formation shows both unabsorbed and embedded low-mass members of the Orion Nebula Cluster, the luminous infrared Source n, and a class of sources without photospheric counterparts that may be new magnetically active embedded PMS stars. Several X-ray sources are also variable radio emitters. Faint X-ray emission is seen close to, but apparently not coincident with the BN object. Its nature is not clear., Comment: 19 pages, 6 figures (3 in color). Accepted for publication in the Astronomical Journal. Electronic version of Table 1, and high-quality versions of Figs. 1 and 6, can be obtained from ftp://ftp.astro.psu.edu/pub/edf/orion

Published
2000
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102. Discovery of Narrow X-ray Absorption Lines from NGC 3783 with the Chandra HETGS

Author

Kaspi, Shai, Brandt, W. N., Netzer, Hagai, Sambruna, Rita, Chartas, George, Garmire, Gordon P., and Nousek, John A.

Subjects
Astrophysics
Abstract

We present the first grating-resolution X-ray spectra of the Seyfert 1 galaxy NGC 3783, obtained with the High Energy Transmission Grating Spectrometer on the Chandra X-ray Observatory. These spectra reveal many narrow absorption lines from the H-like and He-like ions of O, Ne, Mg, Si, S and Ar, as well as FeXVII-FeXXI L-shell lines. We have also identified several weak emission lines, mainly from O and Ne. The absorption lines are blueshifted by a mean velocity of approximately 440\pm200 km/s and are not resolved, indicating a velocity dispersion within the absorbing gas of a few hundred km/s or less. We measure the lines' equivalent widths and compare them with the predictions of photoionization models. The best-fitting model has a microturbulence velocity of 150 km/s and a hydrogen column density of 1.3\times10^22 cm^-2. The measured blueshifts and inferred velocity dispersions of the X-ray absorption lines are consistent with those of the strongest UV absorption lines observed in this object. However, simple models that propose to strictly unify the X-ray and UV absorbers have difficulty explaining simultaneously the X-ray and UV absorption line strengths., Comment: 4 pages, 2 figures included, LaTeX emulateapj5.sty, accepted for publication in the Astrophysical Journal Letters, also available from http://www.astro.psu.edu/users/niel/papers/papers.html

Published
2000

110. Intragroup and Galaxy-linked Diffuse X-ray Emission In Hickson Compact Groups

Author

Desjardins, Tyler D, Gallagher, Sarah C, Tzanavaris, Panayiotis, Mulchaey, John S, Brandt, William N, Charlton, Jane C, Garmire, Gordon P, Gronwall, Caryl, Cardiff, Ann, Johnson, Kelsey E, Konstantopoulos, Iraklis, S, and Zabludoff, Ann I

Subjects
Astronomy, Astrophysics
Abstract

Isolated compact groups (CGs) of galaxies present a range of dynamical states, group velocity dispersions, and galaxy morphologies with which to study galaxy evolution, particularly the properties of gas both within the galaxies and in the intragroup medium. As part of a large, multiwavelength examination of CGs, we present an archival study of diffuse X-ray emission in a subset of nine Hickson compact groups (HCGs) observed with the Chandra X-Ray Observatory. We find that seven of the groups in our sample exhibit detectable diffuse emission. However, unlike large-scale emission in galaxy clusters, the diffuse features in the majority of the detected groups are linked to the individual galaxies, in the form of both plumes and halos likely as a result of vigourous star formation or activity in the galaxy nucleus, as well as in emission from tidal features. Unlike previous studies from earlier X-ray missions, HCGs 31, 42, 59, and 92 are found to be consistent with the L(sub X-Tau) relationship from clusters within the errors, while HCGs 16 and 31 are consistent with the cluster L(sub X-sigma) relation, though this is likely coincidental given that the hot gas in these two systems is largely due to star formation. We find that L(sub X) increases with decreasing group Hi to dynamical-mass ratio with tentative evidence for a dependence in X-ray luminosity on Hi morphology whereby systems with intragroup Hi indicative of strong interactions are considerably more X-ray luminous than passively evolving groups. We also find a gap in the L(sub X) of groups as a function of the total group specific star formation rate. Our findings suggest that the hot gas in these groups is not in hydrostatic equilibrium and these systems are not low-mass analogs of rich groups or clusters, with the possible exception of HCG 62.

Published
2013
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115. X-ray properties of dust-obscured galaxies with broad optical/UV emission lines.

Author

(邹凡), Fan Zou, Brandt, William N, Vito, Fabio, (陳建廷), Chien-Ting Chen, Garmire, Gordon P, Stern, Daniel, and Ayubinia, Ashraf

Subjects
SUPERMASSIVE black holes, GALAXIES, ACTIVE galactic nuclei, GAS reservoirs, X-rays, GALACTIC X-ray sources
Abstract

Dust-obscured galaxies (DOGs) with extreme infrared luminosities may represent a key phase in the co-evolution of galaxies and supermassive black holes. We select 12 DOGs at 0.3 ≲ z ≲ 1.0 with broad Mg  ii or H β emission lines and investigate their X-ray properties utilizing snapshot observations (∼3 ks per source) with Chandra. By assuming that the broad lines are broadened due to virial motions of broad-line regions, we find that our sources generally have high Eddington ratios (λEdd). Our sources generally have moderate intrinsic X-ray luminosities (L X ≲ 1045 erg s−1), which are similar to those of other DOGs, but are more obscured. They also present moderate outflows and intense starbursts. Based on these findings, we conclude that high-λEdd DOGs are closer to the peaks of both host-galaxy and black hole growth compared to other DOGs, and that (active galactic nucleus) AGN feedback has not swept away their reservoirs of gas. However, we cannot fully rule out the possibility that the broad lines are broadened by outflows, at least for some sources. We investigate the relations among L X, AGN rest-frame 6  μ m monochromatic luminosity, and AGN bolometric luminosity, and find the relations are consistent with the expected ones. [ABSTRACT FROM AUTHOR]

Published
2020
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116. CUBIC - A non-dispersive Diffuse X-ray Background spectrometer

Author

Burrows, David N, Skinner, Mark A, Antunes, Alexander J. D, Catalano, Mark A, Cocklin, Eric J, Engel, Leland G, Entingh, Timothy J, Garmire, Gordon P, Green, Roland, and Kelly, Douglas A

Subjects
Spacecraft Instrumentation
Abstract

The Cosmic Unresolved X-ray Background Instrument using CCDs (CUBIC) is designed to obtain spectral observations of the Diffuse X-ray Background (DXRB) with moderate spectral resolution over the energy range 0.2-10 keV, using mechanically-collimated CCDs. At this time, it is the only planned satellite payload devoted to the study of the spectrum of the DXRB. Over the anticipated 3 year lifetime of the satellite, CUBIC will be able to study up to 50 percent of the sky with 5 x 5 deg spatial resolution for the subkilovolt Galactic diffuse background, and with 10 x 10 deg spatial resolution for the extragalactic diffuse background above 2 keV. CUBIC will obtain high quality nondispersive spectra of soft X-ray emission from the interstellar medium, supernova remnants, and some bright sources, and will make a sensitive seach for line emission or other features in the extragalactic cosmic X-ray background from 2-10 keV.

Published
1992

121. Characteristics of Diffuse X-Ray Line Emission within 20 Parsecs of the Galactic Center

Author

Park, Sangwook, Muno, Michael P., Baganoff, Frederick K., 前田, 良知, Morris, Mark, Howard, Christian, Bautz, Mark W., Garmire, Gordon P., Maeda, Yoshitomo, Park, Sangwook, Muno, Michael P., Baganoff, Frederick K., 前田, 良知, Morris, Mark, Howard, Christian, Bautz, Mark W., Garmire, Gordon P., and Maeda, Yoshitomo

Abstract

Accepted: 2003-11-20

Published
2015

122. A Candidate Neutron Star Associated with Galactic Center Supernova Remnant Sagittarius A East

Author

Park, Sangwook, Muno, Michael P., Baganoff, Frederick K., 前田, 良知, Morris, Mark, Chartas, George, Sanwal, Divas, Burrows, David N., Garmire, Gordon P., Maeda, Yoshitomo, Park, Sangwook, Muno, Michael P., Baganoff, Frederick K., 前田, 良知, Morris, Mark, Chartas, George, Sanwal, Divas, Burrows, David N., Garmire, Gordon P., and Maeda, Yoshitomo

Abstract

Accepted: 2005-06-08

Published
2015

123. DISCREPANT MASS ESTIMATES IN THE CLUSTER OF GALAXIES ABELL 1689

Author

MIT Kavli Institute for Astrophysics and Space Research, Peng, En-Hsin, Andersson, Karl, Bautz, Marshall W., Garmire, Gordon P., MIT Kavli Institute for Astrophysics and Space Research, Peng, En-Hsin, Andersson, Karl, Bautz, Marshall W., and Garmire, Gordon P.

Abstract

We present a new mass estimate of a well studied gravitational lensing cluster, Abell 1689, from deep Chandra observations with a total exposure of 200 ks. Within r = 200 h[superscript –1] kpc, the X-ray mass estimate is systematically lower than that of lensing by 30%-50%. At r>200 h[superscript –1] kpc, the mass density profiles from X-ray and weak lensing methods give consistent results. The most recent weak lensing work suggests a steeper profile than what is found from the X-ray analysis, while still in agreement with the mass at large radii. Fitting the total mass profile to a Navarro-Frenk-White model, we find M [subscript 200] = (1.16[superscript +0.45] [subscript –0.27]) × 10[superscript 15] h[superscript –1] M ☉ with a concentration, c 200 = 5.3[superscript +1.3] [subscript –1.2], using nonparametric mass modeling. With parametric profile modeling, we find M 200 = (0.94[superscript +0.11] –0.06) × 10[superscript 15] h[superscript –1] M ☉ and c 200 = 6.6[superscript +0.4] [subscript –0.4]. This is much lower compared to masses deduced from the combined strong and weak lensing analysis. Previous studies have suggested that cooler small-scale structures can bias X-ray temperature measurements or that the northern part of the cluster is disturbed. We find these scenarios unlikely to resolve the central mass discrepancy since the former requires 70%-90% of the space to be occupied by these cool structures, and excluding the northern substructure does not significantly affect the total mass profiles. A more plausible explanation is a projection effect. Assuming that the gas temperature and density profiles have a prolate symmetry, we can bring the X-ray mass estimate into a closer agreement with that of lensing. We also find that the previously reported high hard-band to broadband temperature ratio in A1689, and many other clusters observed with Chandra, may be resulting from the instrumental absorption that decreases 10%-15% of the effective area at ~1.75 keV., Smithsonian Astrophysical Observatory (SAO Award Number 2834-MIT-SAO-4018), United States. National Aeronautics and Space Administration (SAO, under NASA contract NAS 8-03060)

Published
2015

124. An X-ray and Multiwavelength Survey of Highly Radio-Loud Quasars at z > 4: Jet-Linked Emission in the Brightest Radio Beacons of the Early Universe

Author

Wu, Jianfeng, Brandt, W. N., Miller, Brendan P., Garmire, Gordon P., Schneider, Donald P., and Vignali, Cristian

Subjects
Cosmology and Nongalactic Astrophysics (astro-ph.CO), Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics
Abstract

(Abridged) We present a systematic study of the X-ray and multiwavelength properties of a sample of 17 highly radio-loud quasars (HRLQs) at z > 4 with sensitive X-ray coverage from new Chandra and archival Chandra, XMM-Newton, and Swift observations. Eight of the new and archival observations are reported in this work for the first time. New Chandra observations of two moderately radio-loud and highly optically luminous quasars at z > 4 are also reported. Our HRLQ sample represents the top ~5% of radio-loud quasars in terms of radio loudness. We found that our HRLQs have an X-ray emission enhancement over HRLQs at lower redshifts (by a typical factor of ~3), and this effect, after controlling for several factors which may introduce biases, has been solidly estimated to be significant at the 3-4 sigma level. HRLQs at z=3-4 are also found to have a similar X-ray emission enhancement over z < 3 HRLQs, which supports further the robustness of our results. We discuss models for the X-ray enhancement's origin including a fractional contribution from inverse Compton scattering of cosmic microwave background photons. No strong correlations are found between the relative X-ray brightness and optical/UV emission-line rest-frame equivalent widths (REWs) for radio-loud quasars. However, the line REWs are positively correlated with radio loudness, which suggests that relativistic jets make a negligible contribution to the optical/UV continua of these HRLQs (contrary to the case where the emission lines are diluted by the relativistically boosted continuum). Our HRLQs are generally consistent with the known anti-correlation between radio loudness and X-ray power-law photon index. We also found that the two moderately radio-loud quasars appear to have the hardest X-ray spectra among our objects, suggesting that intrinsic X-ray absorption (N_H~10^23 cm^-2) may be present., ApJ in press; 9 figures, 13 tables

Published
2013
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126. DEEPCHANDRA,HST-COS, AND MEGACAM OBSERVATIONS OF THE PHOENIX CLUSTER: EXTREME STAR FORMATION AND AGN FEEDBACK ON HUNDRED KILOPARSEC SCALES

Author

McDonald, Michael, primary, McNamara, Brian R., additional, Weeren, Reinout J. van, additional, Applegate, Douglas E., additional, Bayliss, Matthew, additional, Bautz, Marshall W., additional, Benson, Bradford A., additional, Carlstrom, John E., additional, Bleem, Lindsey E., additional, Chatzikos, Marios, additional, Edge, Alastair C., additional, Fabian, Andrew C., additional, Garmire, Gordon P., additional, Hlavacek-Larrondo, Julie, additional, Jones-Forman, Christine, additional, Mantz, Adam B., additional, Miller, Eric D., additional, Stalder, Brian, additional, Veilleux, Sylvain, additional, and ZuHone, John A., additional

Published
2015
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128. THE MASSIVE STAR-FORMING REGIONS OMNIBUS X-RAY CATALOG

Author

Townsley, Leisa K., primary, Broos, Patrick S., additional, Garmire, Gordon P., additional, Bouwman, Jeroen, additional, Povich, Matthew S., additional, Feigelson, Eric D., additional, Getman, Konstantin V., additional, and Kuhn, Michael A., additional

Published
2014
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130. Coronal X-ray emission from an intermediate-age brown dwarf

Author

Feigelson, Eric D., Garmire, Gordon P., Chartas, George, Pravdo, Steven H., Tsuboi, Yohko, Maeda, Yoshitomo, and Mori, Koji

Subjects
Physics, Image (category theory), Astrophysics::High Energy Astrophysical Phenomena, Astrophysics (astro-ph), X-ray, Brown dwarf, Flux, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Luminosity, Stars, Space and Planetary Science, Astrophysics::Solar and Stellar Astrophysics, Binary system, Astrophysics::Earth and Planetary Astrophysics, Astrophysics::Galaxy Astrophysics
Abstract

Accepted: 2003-02-28, 資料番号: SA1003404000

Published
2003

131. Chandra Evidence of a Flattened, Triaxial Dark Matter Halo in the Elliptical Galaxy NGC 720

Author

delete, Massachusetts Institute of Technology. Department of Physics, MIT Kavli Institute for Astrophysics and Space Research, Canizares, Claude R., Jeltema, Tesla E., Garmire, Gordon P., Buote, David A., delete, Massachusetts Institute of Technology. Department of Physics, MIT Kavli Institute for Astrophysics and Space Research, Canizares, Claude R., Jeltema, Tesla E., Garmire, Gordon P., and Buote, David A.

Abstract

We present an analysis of a Chandra ACIS-S observation of the elliptical galaxy NGC 720, to verify the existence of a dark matter halo and to measure its ellipticity. The ACIS-S3 image reveals over 60 point sources distributed throughout the field, most of which were undetected and therefore unaccounted for in previous X-ray studies. For semimajor axes a [< over ~] 150" (18.2 [-1 over 70] kpc), the ellipticity of the diffuse X-ray emission is consistent with a constant value, ϵ[subscript X] ≈ 0.15, which is systematically less than the values of 0.2-0.3 obtained from previous ROSAT PSPC and HRI observations because of the unresolved point sources contaminating the ROSAT values. The Chandra data confirm the magnitude of the ~20° position angle (P.A.) twist discovered by ROSAT over this region. However, the twist in the Chandra data is more gradual and occurs at smaller a, also because of the point sources contaminating the ROSAT values. For a [> over ~]150" out to a = 185" (22.4 h[-1 over 70] kpc), which is near the edge of the S3 CCD, ϵ[subscript X] and P.A. diverge from their values at smaller a. Possible origins of this behavior at the largest a are discussed. Overall, the ellipticities and P.A. twist for a [< over ~] 150" can be explained by the triaxial mass model of NGC 720 published by Romanowsky & Kochanek (which could not produce the abrupt P.A. twist in the ROSAT HRI data). Since the optical image displays no substantial isophote twisting, the X-ray P.A. twist requires a massive dark matter halo if the hot gas is in hydrostatic equilibrium. Furthermore, the values of ϵ[subscript X] obtained by Chandra are too large to be explained if the gravitating mass follows the optical light (M α L*), irrespective of the P.A. twist. The M α L* hypothesis is inconsistent with the Chandra ellipticities at the 96% confidence level, assuming oblate symmetry, and at the 98% confidence level for prolate symmetry. Thus, both the P.A. twist and the ellipticities of the Chandra, National Science Foundation (U.S.) (Fellowship)

Published
2013

138. THE CHANDRA CARINA COMPLEX PROJECT: DECIPHERING THE ENIGMA OF CARINA'S DIFFUSE X-RAY EMISSION

Author

Townsley, Leisa K., primary, Broos, Patrick S., additional, Chu, You-Hua, additional, Gagné, Marc, additional, Garmire, Gordon P., additional, Gruendl, Robert A., additional, Hamaguchi, Kenji, additional, Mac Low, Mordecai-Mark, additional, Montmerle, Thierry, additional, Nazé, Yaël, additional, Oey, M. S., additional, Park, Sangwook, additional, Petre, Robert, additional, and Pittard, Julian M., additional

Published
2011
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139. A CATALOG OF CHANDRA X-RAY SOURCES IN THE CARINA NEBULA

Author

Broos, Patrick S., primary, Townsley, Leisa K., additional, Feigelson, Eric D., additional, Getman, Konstantin V., additional, Garmire, Gordon P., additional, Preibisch, Thomas, additional, Smith, Nathan, additional, Babler, Brian L., additional, Hodgkin, Simon, additional, Indebetouw, Rémy, additional, Irwin, Mike, additional, King, Robert R., additional, Lewis, Jim, additional, Majewski, Steven R., additional, McCaughrean, Mark J., additional, Meade, Marilyn R., additional, and Zinnecker, Hans, additional

Published
2011
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141. X-RAY STAR CLUSTERS IN THE CARINA COMPLEX

Author

Feigelson, Eric D., primary, Getman, Konstantin V., additional, Townsley, Leisa K., additional, Broos, Patrick S., additional, Povich, Matthew S., additional, Garmire, Gordon P., additional, King, Robert R., additional, Montmerle, Thierry, additional, Preibisch, Thomas, additional, Smith, Nathan, additional, Stassun, Keivan G., additional, Wang, Junfeng, additional, Wolk, Scott, additional, and Zinnecker, Hans, additional

Published
2011
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142. AN INTRODUCTION TO THE CHANDRA CARINA COMPLEX PROJECT

Author

Townsley, Leisa K., primary, Broos, Patrick S., additional, Corcoran, Michael F., additional, Feigelson, Eric D., additional, Gagné, Marc, additional, Montmerle, Thierry, additional, Oey, M. S., additional, Smith, Nathan, additional, Garmire, Gordon P., additional, Getman, Konstantin V., additional, Povich, Matthew S., additional, Evans, Nancy Remage, additional, Nazé, Yaël, additional, Parkin, E. R., additional, Preibisch, Thomas, additional, Wang, Junfeng, additional, Wolk, Scott J., additional, Chu, You-Hua, additional, Cohen, David H., additional, Gruendl, Robert A., additional, Hamaguchi, Kenji, additional, King, Robert R., additional, Mac Low, Mordecai-Mark, additional, McCaughrean, Mark J., additional, Moffat, Anthony F. J., additional, Oskinova, L. M., additional, Pittard, Julian M., additional, Stassun, Keivan G., additional, ud-Doula, Asif, additional, Walborn, Nolan R., additional, Waldron, Wayne L., additional, Churchwell, Ed, additional, Nichols, J. S., additional, Owocki, Stanley P., additional, and Schulz, N. S., additional

Published
2011
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