A5027796962- Galaxies: Formation, Evolution, Phenomena
- Astronomy and Astrophysical Research
- Stellar, planetary, and galactic studies
- Astrophysics and Star Formation Studies
- Gamma-ray bursts and supernovae
- Astrophysical Phenomena and Observations
- Astronomical Observations and Instrumentation
- Astrophysics and Cosmic Phenomena
- Adaptive optics and wavefront sensing
- Spectroscopy and Laser Applications
- Pulsars and Gravitational Waves Research
- CCD and CMOS Imaging Sensors
- Geophysics and Gravity Measurements
- History and Developments in Astronomy
- Scientific Research and Discoveries
- Solar and Space Plasma Dynamics
- Astro and Planetary Science
- Atomic and Molecular Physics
- Plant Water Relations and Carbon Dynamics
- Diversity and Career in Medicine
- Radio Astronomy Observations and Technology
- Phase Equilibria and Thermodynamics
- Superconducting Materials and Applications
- Planetary Science and Exploration
- X-ray Diffraction in Crystallography
Center for Astrophysics Harvard & Smithsonian
2002-2025
ARC Centre of Excellence for All-sky Astrophysics
2017-2024
ASTRO-3D
2017-2024
Australian National University
2015-2024
Mount Stromlo Observatory
1999-2021
ACT Government
2019-2020
Carnegie Observatories
2018
University of Hawaiʻi at Mānoa
2005-2017
University of Hawaii System
2007-2016
Space Telescope Science Institute
2005-2015
We present an analysis of the host properties 85224 emission-line galaxies from Sloan Digital Sky Survey. show that Seyferts and LINERs form clearly separated branches on standard optical diagnostic diagrams. derive a new empirical classification scheme which cleanly separates star-forming galaxies, composite AGN-HII we study galaxy these different classes objects. are older, more massive, less dusty concentrated, have higher velocity dispersions lower [OIII] luminosities than Seyfert...
We have modeled a large sample of infrared starburst galaxies using both the PEGASE v2.0 and STARBURST99 codes to generate spectral energy distribution (SED) young star clusters. utilizes Padova group tracks, while uses Geneva allowing comparison between two. used our MAPPINGS III code compute photoionization models that include self-consistent treatment dust physics chemical depletion. use standard optical diagnostic diagrams as indicators hardness EUV radiation field in these galaxies....
We investigate the effect of metallicity calibrations, AGN classification, and aperture covering fraction on local mass-metallicity (M-Z) relation using 27,730 star-forming galaxies from SDSS Data Release 4. analyze M-Z with 10 including theoretical empirical methods. show that choice calibration has a significant shape y-intercept [12 + log (O/H) ] relation. The absolute scale (y-intercept) varies up to Δ [ = 0.7 dex, depending used, change in is substantial. These results indicate it...
The SIRTF Nearby Galaxy Survey is a comprehensive infrared imaging and spectroscopic survey of 75 nearby galaxies. Its primary goal to characterize the emission galaxies their principal infrared-emitting components, across broad range galaxy properties star formation environments. SINGS will provide new insights into physical processes connecting interstellar medium galaxies, vital foundation for understanding observations distant universe ultraluminous active sample observing strategy have...
We have used a combination of stellar population synthesis and photoionization models to develop set ionization parameter abundance diagnostics based only on the use strong optical emission lines. These are applicable both extragalactic H II regions star-forming galaxies. show that, because our techniques solve explicitly for chemical abundance, presented here an improvement earlier emission-line ratios. Our at all metallicities. In particular, metallicities above half solar, ratio [N II]/[O...
With the goal of investigating degree to which mid-infrared emission traces star formation rate (SFR), we analyze Spitzer 8 um and 24 data star-forming regions in a sample 33 nearby galaxies with available HST/NICMOS images Paschen-alpha (1.8756 um) line. The are drawn from Infrared Nearby Galaxies Survey (SINGS) sample, cover range morphologies factor ~10 oxygen abundance. Published on local low-metallicity starburst Luminous also included analysis. Both stellar-continuum-subtracted...
We present a new library of fully-radiative shock models calculated with the MAPPINGS III and photoionization code. The consists grids velocities in range v=100-1000 km/s magnetic parameters B/sqrt(n) 10^-4 - 10 muG cm^(3/2) for five different atomic abundance sets, pre-shock density 1.0 cm^(-3). Additionally, Solar model have been densities 0.01, 0.1, 10, 100, 1000 cm^(-3) same v B/sqrt(n). Each includes components both radiative its photoionized precursor, ionized by EUV soft X-ray...
We measure nebular oxygen abundances for 204 emission-line galaxies with redshifts 0.3 < z 1.0 in the Great Observatories Origins Deep Survey-North (GOODS-N) field using spectra from Team Keck Redshift Survey. also provide an updated analytic prescription estimating traditional strong emission line ratio, R23, based on photoionization models of Kewley & Dopita. include formula very crude metallicity estimates [N II]λ6584/Hα ratio. Oxygen GOODS-N span range 8.2 ≤ 12 + log(O/H) 9.1,...
In this paper we present the source catalog obtained from a 942 ks exposure of Chandra Deep Field South (CDFS), using Advanced CCD Imaging Spectrometer (ACIS-I) on X-ray Observatory. Eleven individual pointings made between 1999 October and 2000 December were combined to generate final image used for object detection. Catalog generation proceeded simultaneously two different methods; method our own design modified version SExtractor algorithm, wavelet transform technique developed...
We present the results of our spectroscopic follow-up program X-ray sources detected in 942 ks exposure Chandra Deep Field-South (CDFS). A total 288 possible counterparts were observed at VLT with FORS1/FORS2 spectrographs for 251 349 (including three additional faint sources). Spectra and R-band images are shown all R - K colors given most them. Spectroscopic redshifts obtained 168 sources, which 137 have both reliable optical identification redshift estimate 16 external identifications)....
The SAMI Galaxy Survey will observe 3400 galaxies with the Sydney-AAO Multi-object Integral-field spectrograph (SAMI) on Anglo-Australian Telescope (AAT) in a 3-year survey which began 2013. We present throughput of system, science basis and specifications for target selection, observation plan combined properties selected galaxies. includes four volume limited galaxy samples based cuts proxy stellar mass, along low-stellar mass dwarf all from And Mass Assembly (GAMA) survey. GAMA regions...
In this paper, we present high-resolution optical spectra and classifications from our large sample of 285 warm infrared galaxies 108 < LIR 1012.5 L☉. We have classified these using new theoretical lines on the standard diagnostic diagrams. use a extreme mixing line between starburst AGN regions to classify LINER define boundary separating AGNs starbursts. find that many previously as LINERs appear lie sequence type galaxies. These are likely be composite nature with their excitation being...
(Abridged) Far ultraviolet to far infrared images of the nearby galaxy NGC5194, from Spitzer, GALEX, Hubble Space Telescope and ground--based data, are used investigate local global star formation, impact dust extinction in HII-emitting knots. In IR/UV-UV color plane, NGC5194 HII knots show same trend observed for normal star-forming galaxies, having a much larger dispersion than starburst galaxies. We identify as due UV emission predominantly tracing evolved, non-ionizing stellar...
We investigate the [O II] emission line as a star formation rate (SFR) indicator using integrated spectra of 97 galaxies from Nearby Field Galaxies Survey (NFGS). The sample includes all Hubble types and contains SFRs ranging 0.01 to 100 M⊙ yr-1. compare Kennicutt Hα SFR calibrations show that there are two significant effects produce disagreement between SFR([O II]) SFR(Hα): reddening metallicity. Differences in ionization state interstellar medium do not contribute significantly observed...
We use the chemical evolution predictions of cosmological hydrodynamic simulations with our latest theoretical stellar population synthesis, photoionization, and shock models to predict strong line ensembles galaxies from z = 3 present day. In this paper, we focus on brightest optical emission-line ratios, [N ii]/Hα [O iii]/Hβ. diagnostic Baldwin–Phillips–Terlevich (BPT) diagram as a tool for investigating spectral properties active galaxies. four redshift windows chosen exploit new...
The Great Observatories All-Sky LIRG Survey (GOALS20 ) combines data from NASA's Spitzer Space Telescope,Chandra X-Ray Observatory,Hubble Telescope (HST), and Galaxy Evolution Explorer (GALEX) observatories, together with ground-based data, into a comprehensive imaging spectroscopic survey of over 200 low-redshift (z < 0.088), Luminous Infrared Galaxies (LIRGs). LIRGs are complete subset the IRAS Revised Bright Sample (RBGS), which comprises 629 extragalactic objects 60 μm flux densities...
Abstract We present an investigation into the first 500 Myr of galaxy evolution from Cosmic Evolution Early Release Science (CEERS) survey. CEERS, one 13 JWST ERS programs, targets formation z ∼ 0.5 to >10 using several imaging and spectroscopic modes. make use epoch CEERS NIRCam imaging, spanning 35.5 arcmin 2 , search for candidate galaxies at > 9. Following a detailed data reduction process implementing custom steps produce high-quality reduced images, we perform multiband...
We compare the chemical abundances at sites of 12 nearby (z < 0.14) Type Ic supernovae (SN Ic) that showed broad lines, but had no observed gamma-ray burst (GRB), with in five 0.25) galaxies GRBs where broad-lined SN were seen after fireball faded. It has previously been noted GRB hosts are low luminosity and their metal abundances. If metallicity is sufficient to force evolution massive stars end lives as an accompanying Ic, then we would expect higher for have detected GRBs. This what...
Recently, \citet{Nicholls12}, inspired by \emph{in situ} observations of solar system astrophysical plasmas, suggested that the electrons in \HII regions are characterised a $\kappa$-distribution electron energies rather than simple Maxwell-Boltzmann distribution. Here we have collected together new atomic data within modified photoionisation code to explore effects both and on strong-line techniques used determine chemical abundances regions. By comparing recombination temperatures ($T_{\rm...
We report the discovery of a candidate galaxy with photo-z z~12 in first epoch JWST Cosmic Evolution Early Release Science (CEERS) Survey. Following conservative selection criteria we identify source robust z_phot = 11.8^+0.3_-0.2 (1-sigma uncertainty) m_F200W=27.3, and >7-sigma detections five filters. The is not detected at lambda < 1.4um deep imaging from both HST JWST, has faint ~3-sigma F150W F160W, which signal Ly-alpha break near red edge filters, implying z~12. This object (Maisie's...
We compare a large sample of galaxies between 0.5<z<2.6 with theoretical predictions for how the optical diagnostic line ratios in galaxy ensembles change as function cosmic time. show that star forming at high redshift (z>1.5) are consistent model which ISM conditions more extreme than seen global spectra local galaxies. speculate our may be dominated by HII regions similar to clumpy, dense star-forming complexes Antennae and M82. The transition local-type occurs 0.8<z<1.5. conclude...
The relationship between galaxy star formation rates (SFR) and stellar masses ($M_\ast$) is re-examined using a mass-selected sample of $\sim$62,000 star-forming galaxies at $z \le 1.3$ in the COSMOS 2-deg$^2$ field. Using new far-infrared photometry from $Herschel$-PACS SPIRE $Spitzer$-MIPS 24 $\mu$m, along with derived infrared luminosities NRK method based on galaxies' locations restframe color-color diagram $(NUV - r)$ vs. $(r K)$, we are able to more accurately determine total SFRs for...
We present the first results from a near-IR spectroscopic survey of COSMOS field, using Fiber Multi-Object Spectrograph on Subaru telescope, designed to characterize star-forming galaxy population at $1.4<z<1.7$. The high-resolution mode is implemented detect H$\alpha$ in emission between $1.6{\rm -}1.8 \mathrm{\mu m}$ with $f_{\rm H\alpha}\gtrsim4\times10^{-17}$ erg cm$^{-2}$ s$^{-1}$. Here, we specifically focus 271 sBzK-selected galaxies that yield detection thus providing redshift and...
We examine the mass–metallicity relation for z ≲ 1.6. The follows a steep slope with turnover, or "knee," at stellar masses around 1010 M☉. At higher than characteristic turnover mass, flattens as metallicities begin to saturate. show that redshift evolution of depends only on mass. relationship between metallicity and mass normalized is independent redshift. find redshift-independent set by gas in occurs when gas-phase oxygen abundance high enough amount locked up low-mass stars an...