A5070689068- Astrophysical Phenomena and Observations
- Galaxies: Formation, Evolution, Phenomena
- Astronomy and Astrophysical Research
- Astrophysics and Cosmic Phenomena
- Gamma-ray bursts and supernovae
- Stellar, planetary, and galactic studies
- Astronomical Observations and Instrumentation
- Astrophysics and Star Formation Studies
- History and Developments in Astronomy
- Impact of Light on Environment and Health
- Crystallography and Radiation Phenomena
- Radio Astronomy Observations and Technology
- Financial Markets and Investment Strategies
- Complex Systems and Time Series Analysis
- Remote Sensing in Agriculture
- Adaptive optics and wavefront sensing
- Advanced X-ray Imaging Techniques
- Economic theories and models
- Mechanical Engineering and Vibrations Research
- Atmospheric Ozone and Climate
Max Planck Institute for Astrophysics
2011-2016
Harvard University
2012-2014
Durham University
2013-2014
Center for Astrophysics Harvard & Smithsonian
2012-2014
Smithsonian Astrophysical Observatory
2013-2014
Max Planck Society
2013
Based on a homogeneous set of X-ray, infrared and ultraviolet observations from Chandra, Spitzer, GALEX 2MASS archives, we study populations high-mass X-ray binaries (HMXBs) in sample 29 nearby star-forming galaxies their relation to the star-formation rate (SFR). In agreement with previous results, find that HMXBs are good tracer recent activity host galaxy collective luminosity number scale SFR: particular, . However, scaling relations still bear rather large dispersion rms ∼ 0.4 dex,...
The cosmological 21 cm signal is a physics-rich probe of the early Universe, encoding information about both ionization and thermal history intergalactic medium (IGM). latter likely governed by X-rays from star formation processes inside very high redshift (z ≳ 15) galaxies. Due to strong dependence mean free path on photon energy, X-ray spectral energy distribution (SED) can have significant impact interferometric cosmic dawn. Recent Chandra observations nearby, star-forming galaxies show...
We investigate the relation between total X-ray emission from star-forming galaxies and their star formation activity. Using nearby late-type ULIRGs Paper I Chandra Deep Fields, we construct a sample of 66 spanning redshift range z~0-1.3 star-formation rate (SFR) ~0.1-10^3 M_sun/yr. In agreement with previous results, find that Lx-SFR is consistent linear law both at z=0 for z=0.1-1.3 CDF galaxies, within statistical accuracy ~0.1 in slope relation. For sample, scaling Lx/SFR~(4.0\pm...
We study the emission from hot interstellar medium in a sample of nearby late type galaxies defined Paper I. Our covers broad range star formation rates, ~0.1 Msun/yr to ~17 and stellar masses, ~3x10^8 Msun ~6x10^10 Msun. take special care systematic effects contamination bright faint compact sources. find that all at least one optically thin thermal component is present unresolved emission, with average temperature <kT>= 0.24 keV. In about ~1/3 galaxies, second, higher required, 0.71...
We present measurements of the evolution normal-galaxy X-ray emission from $z \approx$ 0-7 using local galaxies and galaxy samples in 6 Ms Chandra Deep Field-South (CDF-S) survey. The majority CDF-S are observed at rest-frame energies above 2 keV, where is expected to be dominated by binary (XRB) populations; however, hot gas provide small contributions observed- frame < 1 keV 1$. show that a single scaling relation between luminosity ($L_{\rm X}$) star-formation rate (SFR) insufficient for...
We report significant anisotropies in the projected two-dimensional (2D) spatial distributions of globular clusters (GCs) giant Virgo elliptical galaxy NGC 4649 (M60). Similar features are found 2D distribution low-mass X-ray binaries (LMXBs), both associated with GCs and stellar field. Deviations from azimuthal symmetry suggest an arc-like excess extending north at 4–15 kpc galactocentric radii eastern side major axis 4649. This feature is more prominent for red GCs, but still persists blue...
We investigate the radial distribution of low-mass X-ray binary (LMXB) population in elliptical galaxy NGC 4649, using Chandra and Hubble data to separate field globular cluster (GC) populations. GCs with LMXBs have same as parent red blue GCs. The profile follows V-band within D25 4649. Using spatial information provided by our data, we find that global galaxy-wide relations among cumulative number luminosity integrated stellar mass hold on local scales D25. An excess respect light is...
We present results from a Chandra study of ultraluminous X-ray sources (ULXs) in sample 17 nearby (D_L<60 Mpc) luminous infrared galaxies (LIRGs), selected to have star formation rates (SFRs) excess 7 M_sun yr^-1 and low foreground Galactic column densities (N_H < 5*10^20 cm^-2). A total 53 ULXs were detected we confirm that this is complete catalogue for the LIRG sample. examine evolution ULX spectra with luminosity by stacking individual objects three bins, finding distinct change spectral...
Abstract We study the relation between X‐ray luminosity of compact sources and SFR host galaxy. Our sample includes 38 galaxies for which a uniform set X‐ray, infra‐red ultraviolet data from Chandra, Spitzer GALEX has been collected. primary goals are (i) to obtain more accurate calibration L x –SFR (ii) understand origin dispersion in observed previous studies. Preliminary results this project reported below (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
We present a new method for the determination of two-dimensional (2D) projected spatial distribution globular clusters (GCs) in external galaxies. This is based on K-Nearest Neighbor density estimator Dressler (1980), complemented by MonteCarlo simulations to establish statistical significance results. apply this NGC4261, "test galaxy" where significant 2D anisotropy GC has been reported. confirm that not azimuthally isotropic. Moreover, we demonstrate departures from average radial results...
Abstract Some empirical studies suggest that the computation of certain graph structures from a (large) historical correlation matrix can be helpful in portfolio selection. In particular, repeated finding is information about weights minimum variance (MVP) classical Markowitz theory inferred measurements centrality such structures. The present article compares two concepts purely algebraic perspective. It demonstrated this heuristic relationship between and MVP does not originate structural...
The colliding galaxy pair NGC 2207/IC 2163, at a distance of ∼39 Mpc, was observed with Chandra, and an analysis reveals 28 well resolved X-ray sources, including 21 ultraluminous sources (ULXs) LX ≳ 1039 erg s−1, as the nucleus 2207. number ULXs is comparable largest numbers per unit mass in any yet reported. In this paper we report on these quantify how their locations correlate local star formation rates seen spatially rate density images that have constructed using combinations GALEX FUV...
We present a comprehensive study of the total X-ray emission from colliding galaxy pair NGC2207/IC2163, based on Chandra, Spitzer, and GALEX data. detect 28 ultra-luminous sources (ULXs), 7 which were not detected previously due to variability. Twelve show significant long-term variability, with no correlated spectral changes. Seven are transient candidates. One ULX coincides an extremely blue star cluster (B-V = -0.7). confirm that global relation between number luminosity ULXs integrated...
In this paper, we report accurate Chandra positions for two ultraluminous X-ray sources (ULXs): NGC 7319-X4 at Right Ascension (RA) = 339°.029 17(2), Declination (Dec.) 33°.974 76(2) and 5474-X1 RA 211°.248 59(3), Dec. 53°.635 84(3). We perform bore-sight corrections on the satellite observations of these to get match with archival optical data from Wide Field Planetary Camera 2 (WFPC2) onboard Hubble Space Telescope. do not find counterparts; limiting absolute magnitudes in WFPC2 standard...