Mark Seibert
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View article: The TYPHOON Stellar Population Synthesis Survey. II. Pushing Full Spectral Fitting to the Limit in the Nearby Grand Design Barred Spiral M83
The TYPHOON Stellar Population Synthesis Survey. II. Pushing Full Spectral Fitting to the Limit in the Nearby Grand Design Barred Spiral M83 Open
We apply population synthesis techniques to analyze TYPHOON long slit spectra of the starburst barred spiral galaxy M83. The analysis covers a central square of 5′ side length. We determine the spatial distribution of dust through the anal…
View article: The TYPHOON Stellar Population Synthesis Survey. II. Pushing Full Spectral Fitting to the Limit in the Nearby Grand Design Barred Spiral M83
The TYPHOON Stellar Population Synthesis Survey. II. Pushing Full Spectral Fitting to the Limit in the Nearby Grand Design Barred Spiral M83 Open
We apply population synthesis techniques to analyze TYPHOON long slit spectra of the starburst barred spiral galaxy M83. The analysis covers a central square of 5 arcmin side length. We determine the spatial distribution of dust through th…
View article: The spatially resolved relation between dust, gas, and metal abundance with the TYPHOON survey
The spatially resolved relation between dust, gas, and metal abundance with the TYPHOON survey Open
We present the spatially resolved relationship between the dust-to-gas mass ratio (DGR) and gas-phase metallicity ($Z_{\rm gas}$ or 12 + log(O/H)) (i.e. DGR–$Z_{\rm gas}$ relation) of 11 nearby galaxies with a large-metallicity range (1.5 …
View article: The spatially resolved relation between dust, gas, and metal abundance with the TYPHOON survey
The spatially resolved relation between dust, gas, and metal abundance with the TYPHOON survey Open
We present the spatially resolved relationship between the dust-to-gas mass ratio (DGR) and gas-phase metallicity (Zgas or 12+log(O/H)) (i.e., DGR-Zgas relation) of 11 nearby galaxies with a large metallicity range (1.5 dex of 12+log(O/H))…
View article: Quantifying azimuthal variations within the interstellar medium of z ~ 0 spiral galaxies with the TYPHOON survey
Quantifying azimuthal variations within the interstellar medium of z ~ 0 spiral galaxies with the TYPHOON survey Open
Most star formation in the local Universe occurs in spiral galaxies, but their origin remains an unanswered question. Various theories have been proposed to explain the development of spiral arms, each predicting different spatial distribu…
View article: The TYPHOON Stellar Population Synthesis Survey. I. The Young Stellar Population of the Great Barred Spiral NGC 1365
The TYPHOON Stellar Population Synthesis Survey. I. The Young Stellar Population of the Great Barred Spiral NGC 1365 Open
We analyze TYPHOON long-slit-absorption line spectra of the starburst barred spiral galaxy NGC 1365 obtained with the Progressive Integral Step Method covering an area of 15 kpc 2 . Applying a population synthesis technique, we determine t…
View article: The TYPHOON stellar population synthesis survey: I. The young stellar population of the Great Barred Spiral NGC 1365
The TYPHOON stellar population synthesis survey: I. The young stellar population of the Great Barred Spiral NGC 1365 Open
We analyze TYPHOON long slit absorption line spectra of the starburst barred spiral galaxy NGC 1365 obtained with the Progressive Integral Step Method covering an area of 15 square kpc. Applying a population synthesis technique, we determi…
View article: Metallicity gradient of barred galaxies with TYPHOON
Metallicity gradient of barred galaxies with TYPHOON Open
Bars play an important role in mixing material in the inner regions of galaxies and stimulating radial migration. Previous observations have found evidence for the impact of a bar on metallicity gradients but the effect is still inconclusi…
View article: Metallicity Gradient of Barred Galaxies with TYPHOON
Metallicity Gradient of Barred Galaxies with TYPHOON Open
Bars play an important role in mixing material in the inner regions of galaxies and stimulating radial migration. Previous observations have found evidence for the impact of a bar on metallicity gradients but the effect is still inconclusi…
View article: Metallicity, Ionization Parameter, and Pressure Variations of H ii Regions in the TYPHOON Spiral Galaxies: NGC 1566, NGC 2835, NGC 3521, NGC 5068, NGC 5236, and NGC 7793
Metallicity, Ionization Parameter, and Pressure Variations of H ii Regions in the TYPHOON Spiral Galaxies: NGC 1566, NGC 2835, NGC 3521, NGC 5068, NGC 5236, and NGC 7793 Open
We present a spatially resolved H ii region study of the gas-phase metallicity, ionization parameter, and interstellar medium (ISM) pressure maps of six local star-forming and face-on spiral galaxies from the TYPHOON program. Self-consiste…
View article: Distances to Local Group Galaxies via Population II, Stellar Distance Indicators. II. The Fornax Dwarf Spheroidal*
Distances to Local Group Galaxies via Population II, Stellar Distance Indicators. II. The Fornax Dwarf Spheroidal* Open
We determine three independent Population II distance moduli to the Fornax dwarf spheroidal (dSph) galaxy, using wide-field, ground-based VI imaging acquired with the Magellan-Baade telescope at Las Campanas Observatory. After subtracting …
View article: Galaxy And Mass Assembly (GAMA): Data Release 4 and the <i>z</i> &lt; 0.1 total and <i>z</i> &lt; 0.08 morphological galaxy stellar mass functions
Galaxy And Mass Assembly (GAMA): Data Release 4 and the <i>z</i> < 0.1 total and <i>z</i> < 0.08 morphological galaxy stellar mass functions Open
In Galaxy And Mass Assembly Data Release 4 (GAMA DR4), we make available our full spectroscopic redshift sample. This includes 248 682 galaxy spectra, and, in combination with earlier surveys, results in 330 542 redshifts across five sky r…
View article: A "blue ring nebula" surrounding a thousands of years old stellar merger
A "blue ring nebula" surrounding a thousands of years old stellar merger Open
Stellar mergers are a brief-lived but common phase in the evolution of binary star systems. Among the many astrophysical implications of these events include the creation of atypical stars (e.g. magnetic stars, blue stragglers, rapid rotat…
View article: Systematic Variations of CO J=2-1/1-0 Ratio and Their Implications in The Nearby Barred Spiral Galaxy M83
Systematic Variations of CO J=2-1/1-0 Ratio and Their Implications in The Nearby Barred Spiral Galaxy M83 Open
We present spatial variations of the CO J = 2−1/1–0 line ratio (R_(21/10)) in the barred spiral galaxy M83 using Total Power Array (single-dish telescopes) data from the Atacama Large Millimeter/submillimeter Array. While the intensities o…
View article: The Carnegie-Chicago Hubble Program. VII. The Distance to M101 via the Optical Tip of the Red Giant Branch Method<sup>*</sup>
The Carnegie-Chicago Hubble Program. VII. The Distance to M101 via the Optical Tip of the Red Giant Branch Method<sup>*</sup> Open
The Carnegie-Chicago Hubble Program (CCHP) is building a direct path to the Hubble constant ( H 0 ) using Population II stars as the calibrator of the Type Ia supernova (SN Ia)-based distance scale. This path to calibrate the SNe Ia is ind…
View article: Standard Galactic field RR Lyrae II: a Gaia DR2 calibration of the period–Wesenheit–metallicity relation
Standard Galactic field RR Lyrae II: a Gaia DR2 calibration of the period–Wesenheit–metallicity relation Open
RR Lyrae stars have long been popular standard candles, but significant advances in methodology and technology have been made in recent years to increase their precision as distance indicators. We present multiwavelength (optical UBVRcIc a…
View article: The Carnegie-Chicago Hubble Program. VIII. An Independent Determination of the Hubble Constant Based on the Tip of the Red Giant Branch*
The Carnegie-Chicago Hubble Program. VIII. An Independent Determination of the Hubble Constant Based on the Tip of the Red Giant Branch* Open
We present a new and independent determination of the local value of the Hubble constant based on a calibration of the tip of the red giant branch (TRGB) applied to Type Ia supernovae (SNe Ia). We find a value of H 0 = 69.8 ± 0.8 (±1.1% st…
View article: The effects of diffuse ionized gas and spatial resolution on metallicity gradients: TYPHOON two-dimensional spectrophotometry of M83
The effects of diffuse ionized gas and spatial resolution on metallicity gradients: TYPHOON two-dimensional spectrophotometry of M83 Open
We present a systematic study of the diffuse ionized gas (DIG) in M83 and its effects on the measurement of metallicity gradients at varying resolution scales. Using spectrophotometric data cubes of M83 obtained at the 2.5m duPont telescop…
View article: The Carnegie–Chicago Hubble Program. V. The Distances to NGC 1448 and NGC 1316 via the Tip of the Red Giant Branch<sup>∗</sup>
The Carnegie–Chicago Hubble Program. V. The Distances to NGC 1448 and NGC 1316 via the Tip of the Red Giant Branch<sup>∗</sup> Open
The Carnegie–Chicago Hubble Program (CCHP) is recalibrating the extragalactic SN Ia distance scale using exclusively Population II stars. This effort focuses on the Tip of the Red Giant Branch (TRGB) method, whose systematics are entirely …
View article: Azimuthal variations of gas-phase oxygen abundance in NGC 2997
Azimuthal variations of gas-phase oxygen abundance in NGC 2997 Open
The azimuthal variation of the H II region oxygen abundance in spiral galaxies is a key observable for understanding how quickly oxygen produced by massive stars can be dispersed within the surrounding interstellar medium. Observational co…
View article: Starburst–AGN mixing: TYPHOON observations of NGC 1365, NGC 1068, and the effect of spatial resolution on the AGN fraction
Starburst–AGN mixing: TYPHOON observations of NGC 1365, NGC 1068, and the effect of spatial resolution on the AGN fraction Open
We demonstrate a robust method of resolving the star-formation and AGN\ncontributions to emission lines using two very well known AGN systems: NGC\n1365, and NGC 1068, using the high spatial resolution data from the\nTYPHOON/PrISM survey. …
View article: Near-identical star formation rate densities from Hα and FUVat redshift zero
Near-identical star formation rate densities from Hα and FUVat redshift zero Open
For the first time both H$\\alpha$ and far-ultraviolet (FUV) observations from\nan HI-selected sample are used to determine the dust-corrected star formation\nrate density (SFRD: $\\dot{\\rho}$) in the local Universe. Applying the two star…
View article: SMHASH: anatomy of the Orphan Stream using RR Lyrae stars
SMHASH: anatomy of the Orphan Stream using RR Lyrae stars Open
Stellar tidal streams provide an opportunity to study the motion and\nstructure of the disrupting galaxy as well as the gravitational potential of\nits host. Streams around the Milky Way are especially promising as phase space\npositions o…
View article: The Near-infrared Tip of the Red Giant Branch. I. A Calibration in the Isolated Dwarf Galaxy IC 1613
The Near-infrared Tip of the Red Giant Branch. I. A Calibration in the Isolated Dwarf Galaxy IC 1613 Open
Based on observations from the FourStar near-infrared camera on the 6.5 m Baade-Magellan telescope at Las Campanas, Chile, we present calibrations of the JHK luminosities of stars defining the tip of the red giant branch (TRGB) in the halo…
View article: The Near-infrared Tip of the Red Giant Branch. II. An Absolute Calibration in the Large Magellanic Cloud
The Near-infrared Tip of the Red Giant Branch. II. An Absolute Calibration in the Large Magellanic Cloud Open
We present a new empirical JHK absolute calibration of the tip of the red giant branch (TRGB) in the Large Magellanic Cloud (LMC). We use published data from the extensive Near-Infrared Synoptic Survey containing 3.5 million stars, 65,000 …
View article: The Carnegie–Chicago Hubble Program. III. The Distance to NGC 1365 via the Tip of the Red Giant Branch<sup>∗</sup>
The Carnegie–Chicago Hubble Program. III. The Distance to NGC 1365 via the Tip of the Red Giant Branch<sup>∗</sup> Open
The Carnegie–Chicago Hubble Program (CCHP) seeks to anchor the distance scale of Type Ia supernovae via the Tip of the Red Giant Branch (TRGB) method. Based on deep Hubble Space Telescope ACS/WFC imaging, we present an analysis of the TRGB…
View article: The Rise and Peak of the Luminous Type IIn SN 2017hcc/ATLAS17lsn from ASAS-SN and Swift UVOT Data
The Rise and Peak of the Luminous Type IIn SN 2017hcc/ATLAS17lsn from ASAS-SN and Swift UVOT Data Open
We present observations of the rise and peak of the Type IIn supernova SN 2017hcc/ATLAS17lsn obtained by the All-Sky Automated Survey for Supernovae (ASAS-SN) and Swift UVOT. The light curve of SN 2017hcc/ATLAS17lsn peaks at $V\\simeq 13.7…
View article: The Rise and Peak of the Luminous Type IIn SN 2017hcc/ATLAS17lsn from ASAS-SN and Swift UVOT Data
The Rise and Peak of the Luminous Type IIn SN 2017hcc/ATLAS17lsn from ASAS-SN and Swift UVOT Data Open
We present observations of the rise and peak of the Type IIn supernova SN 2017hcc/ATLAS17lsn obtained by the All-Sky Automated Survey for Supernovae (ASAS-SN) and Swift UVOT. The light curve of SN 2017hcc/ATLAS17lsn peaks at $V\simeq 13.7$…
View article: SDSS-V: Pioneering Panoptic Spectroscopy
SDSS-V: Pioneering Panoptic Spectroscopy Open
SDSS-V will be an all-sky, multi-epoch spectroscopic survey of over six million objects. It is designed to decode the history of the Milky Way, trace the emergence of the chemical elements, reveal the inner workings of stars, and investiga…
View article: The Carnegie-Chicago Hubble Program. II. The Distance to IC 1613: The Tip of the Red Giant Branch and RR Lyrae Period–luminosity Relations*
The Carnegie-Chicago Hubble Program. II. The Distance to IC 1613: The Tip of the Red Giant Branch and RR Lyrae Period–luminosity Relations* Open
IC 1613 is an isolated dwarf galaxy within the Local Group. Low foreground and internal extinction, low metallicity, and low crowding make it an invaluable testbed for the calibration of the local distance ladder. We present new, high-fide…