A5049281414- Astronomy and Astrophysical Research
- Galaxies: Formation, Evolution, Phenomena
- Astrophysical Phenomena and Observations
- Stellar, planetary, and galactic studies
- Gamma-ray bursts and supernovae
- Astronomical Observations and Instrumentation
- Astrophysics and Star Formation Studies
- Electron and X-Ray Spectroscopy Techniques
- Nuclear Physics and Applications
- Laser-induced spectroscopy and plasma
- Astrophysics and Cosmic Phenomena
- Cosmology and Gravitation Theories
- Scientific Research and Discoveries
- Statistical and numerical algorithms
- Geophysics and Sensor Technology
Pennsylvania State University
2025
University of Arkansas at Fayetteville
2019-2023
Abstract Using a recent Chandra ACIS observation of the eclipsing cataclysmic variable (CV) V1460 Her (2MASS J16211735+4412541) with fast-rotating ( P spin = 38.9 s) white dwarf, we estimated flux <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mi>F</mml:mi> </mml:mrow> <mml:mn>0.5</mml:mn> <mml:mo>–</mml:mo> <mml:mn>7</mml:mn> <mml:mspace width="0.25em"/> <mml:mi mathvariant="normal">keV</mml:mi> mathvariant="normal">abs</mml:mi>...
We present a morphological analysis of ALMA and JWST NIRCam images nine dusty star-forming galaxies (DSFGs) at zspec=3.09, all embedded within the cosmic web filaments SSA22 proto-cluster core. The 870um 1.1mm are obtained spatial resolutions ranging from 0.5" to 0.05" (350 pc z=3.09). high-resolution enable us resolve inner structures traced by dust continuum, identifying compact cores, clumps, offset ridges bars. Sersic profile fit was performed for both F444W comparable (0.15"). index...
Abstract In the present-day universe, most massive galaxies are ellipticals located in cores of galaxy clusters, harboring heaviest super-massive black holes (SMBHs). However, mechanisms that drive early growth phase and subsequent transformation morphology kinematics remain elusive. Here we report (sub)kiloparsec-scale observations stars, gas, dust ADF22.A1, a bright dusty starburst at $z=3.1$, hosting heavily obscured active galactic nucleus residing proto-cluster core. ADF22.A1 is giant...
Abstract We investigate X-ray binary (XRB) luminosity function (XLF) scaling relations for Chandra-detected populations of low-mass XRBs (LMXBs) within the footprints 24 early-type galaxies. Our sample includes Chandra and Hubble Space Telescope observed galaxies at Mpc that have estimates globular cluster (GC) specific frequency ( S N ) reported in literature. As such, we are able to directly classify X-ray-detected sources as being coincident with unrelated background/foreground objects,...
Abstract We present an updated version of Lightning , a galaxy spectral energy distribution (SED) fitting code that can model X-ray to submillimeter observations. The models in include the options contain contributions from stellar populations, dust attenuation and emission, active galactic nuclei (AGNs). when utilized, be modeled as originating compact binary populations with option emission AGNs. have also included variety algorithms fit observations sample parameter posteriors; these...
Abstract We analyze the physical properties of eight X-ray-selected active galactic nuclei (AGNs) and one candidate protoquasar system (ADF22A1) in z = 3.09 SSA22 protocluster by fitting their X-ray-to-IR spectral energy distributions (SEDs) using our SED-fitting code, Lightning ( https://www.github.com/rafaeleufrasio/lightning ). recover star formation histories (SFHs) for seven these systems which are well fit composite stellar population plus AGN models. find indications that four out...
The density-wave theory of spiral structure proposes that star formation occurs in or near a spiral-shaped region higher density rotates rigidly within the galactic disk at fixed pattern speed. In most interpretations this theory, newborn stars move downstream position as they come into view, forming which is tighter, with smaller pitch angle than wave itself. Rival theories, including theories see arms essentially transient structures, may demand should not depend on wavelength. We measure...
ABSTRACT Quasi-stationary density wave theory predicts the existence of an age gradient across spiral arms with a phase crossing at corotation radius. We have examined evidence for such gradients using star formation history (SFH) maps derived from lightning, spectral energy distribution fitting procedure, and by spatially resolved stellar clusters. Three galaxies LEGUS survey were used to analyse azimuthal offsets Kernel estimation plots cluster distance reveal prominent central peaks...
The spiral arms spanning disk galaxies are believed to be created by density waves that propagate through galactic disks. We present a novel method of finding the co-rotation radius where arm pattern speed matches velocities stars within disk. Our uses an image-overlay technique, which involves tracing on images observed in different wavelengths. Density wave theory predicts from wavelengths show phase crossing at radius. For purpose this study, 20 nearby were analyzed four with pitch angle...
We examine possible environmental sources of the enhanced star formation and active galactic nucleus (AGN) activity in $z = 3.09$ SSA22 protocluster using Hubble WFC3 F160W ($\sim1.6\ \rm \mu m$) observations field, including new centered on eight X-ray selected AGN. To investigate role mergers observed AGN enhancement, we apply both quantitative (S\'ersic-fit Gini-$M_{20}$) visual morphological classifications to images Lyman break galaxies (LBGs) fields \sim 3$ field LBGs GOODS-N. find no...
We develop and implement an inclination-dependent attenuation prescription for spectral energy distribution (SED) fitting study its impact on derived star-formation histories. apply our within the SED code Lightning to a clean sample of 82, z=0.21-1.35 disk-dominated galaxies in Great Observatories Origins Deep Survey North South fields. To compare with more traditional prescriptions, we also fit SEDs inclination-independent Calzetti et al. (2000) curve. From this comparison, find that fits...
Abstract We examine and quantify how hybrid (e.g., UV+IR) star formation rate (SFR) estimators the A FUV – β relation depend on inclination for disk-dominated galaxies using spectral energy distribution modeling that utilizes inclination-dependent attenuation curves described in Doore et al. perform this analysis a sample of 133 from CANDELS fields 18 disk Spitzer Infrared Nearby Galaxies Survey Key Insights Galaxies: Far-Infrared with Herschel samples. find both SFR present clear...
We present a new empirical framework modeling the metallicity and star-formation history (SFH) dependence of X-ray luminous ($L > 10^{36}$ ergs s$^{-1}$) point-source population luminosity functions (XLFs) in normal galaxies. expect populations are dominated by binaries (XRBs), with contributions from supernova remnants near low end our observations. Our is calibrated using collective statistical power 3,731 detected point-sources within 88 Chandra-observed galaxies at $D <$ 40 Mpc that span...
In the present-day universe, most massive galaxies are ellipticals located in cores of galaxy clusters, harboring heaviest super-massive black holes (SMBHs). However mechanisms that drive early growth phase and subsequent transformation these morphology kinematics remain elusive. Here we report (sub)kiloparsec scale observations stars, gas, dust ADF22.A1, a bright dusty starburst at z=3.1, hosting heavily obscured active galactic nucleus residing proto-cluster core. ADF22.A1 is giant spiral...
Abstract We present a new empirical framework modeling the metallicity and star formation history (SFH) dependence of X-ray luminous ( L ≳ 10 36 erg s −1 ) point-source population luminosity functions (XLFs) in normal galaxies. expect that populations are dominated by binaries (XRBs), with contributions from supernova remnants near low end our observations. Our is calibrated using collective statistical power 3731 detected point sources within 88 Chandra-observed galaxies at D ≲ 40 Mpc span...
Using a recent Chandra ACIS observation of the eclipsing cataclysmic variable (CV) V1460 Her (2MASS J16211735+4412541) with fast-rotating ($P_{\rm spin} = 38.9$~s) white dwarf, we estimated flux $F_{0.5-7 {\rm keV}}^{\rm abs} (1.9\pm 0.5)\times 10^{-14}$ erg cm$^{-2}$ s$^{-1}$, factor $\sim7$ lower than found from previous Swift XRT observations $\approx8$ years ago, when CV was quiescent. The drop in suggests corresponding accretion rate, and resulting intrinsic luminosity $L_{0.5-7 keV}}...
We analyze the physical properties of 8 X-ray selected active galactic nuclei (AGN) and one candidate protoquasar system (ADF22A1) in $z = 3.09$ SSA22 protocluster by fitting their X-ray-to-IR spectral energy distributions (SEDs) using our SED code, Lightning. recover star formation histories (SFH) for 7 these systems which are well-fit composite stellar population plus AGN models. find indications that 4/9 we study have host galaxies below main sequence, with $\rm SFR/SFR_{MS} \leq -0.4$....
We present an updated version of Lightning, a galaxy spectral energy distribution (SED) fitting code that can model X-ray to submillimeter observations. The models in Lightning include the options contain contributions from stellar populations, dust attenuation and emission, active galactic nuclei (AGN). when utilized, be modeled as originating compact binary populations with option emission AGN. have also included variety algorithms fit observations sample parameter posteriors; these...