Gerhardt R. Meurer
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The organizations/institutes from the scholar's latest article
Previous Organizations / Institutes
The organizations / institutes from the scholar's other articles in the past ten years
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Gerhardt R. Meurer has a total of 8 co-authors. Here are the top co-authors by number of shared publications:
A. Kinney
Department of Physics and Astronomy Département de Physique Observatoire du Mont Mégantic Astronomy Department The Johns Hopkins University Space Telescope Science Institute Université Laval University of Minnesota
1 shared publication- C. Carignan
Département de Physique and Observatoire du Mont Mégantic Université de Montréal C.P. 6128, Succ. "A", Montréal H3C 3J7 Québec Canada
1 shared publication C. Leitherer
Department of Physics and Astronomy Département de Physique Observatoire du Mont Mégantic Astronomy Department The Johns Hopkins University Space Telescope Science Institute Université Laval University of Minnesota
1 shared publicationC. Robert
Department of Physics and Astronomy Département de Physique Observatoire du Mont Mégantic Astronomy Department The Johns Hopkins University Space Telescope Science Institute Université Laval University of Minnesota
1 shared publicationD. R. Garnett
Department of Physics and Astronomy Département de Physique Observatoire du Mont Mégantic Astronomy Department The Johns Hopkins University Space Telescope Science Institute Université Laval University of Minnesota
1 shared publication- K. C. Freeman
Mount Stromlo and Siding Spring Observatories, Australian National University, Weston, ACT 2611, Australia
1 shared publication
Latest Publications
- Open Access
The Case For Substantial Dust Extinction At z ~ 3
Estimates of the total metal production rate (\dot{\rho}_Z) and star formation rate at z > 2 are based on Lyman break systems observed in the rest-frame ultraviolet (UV). These observations are very sensitive to dust obscuration. Here I elucidate and refine the Meurer et al. (1997) method for calculating UV obscuration, presenting new relationships which accurately model the dust reprocessing of radiation in local starbursts. The median lambda = 1600 Angstroms obscuration factor is ~10 at z ~ 3 which is shown to be consistent with other constraints on the high-z \dot{\rho}_Z. Two tests are proposed to further constrain \dot{\rho}_Z at these redshifts.
Open AccessThe Case For Substantial Dust Extinction At z ~ 3
Estimates of the total metal production rate (\dot{\rho}_Z) and star formation rate at z > 2 are based on Lyman break systems observed in the rest-frame ultraviolet (UV). These observations are very sensitive to dust obscuration. Here I elucidate and refine the Meurer et al. (1997) method for calculating UV obscuration, presenting new relationships which accurately model the dust reprocessing of radiation in local starbursts. The median lambda = 1600 Angstroms obscuration factor is ~10 at z ~ 3 which is shown to be consistent with other constraints on the high-z \dot{\rho}_Z. Two tests are proposed to further constrain \dot{\rho}_Z at these redshifts.
- Open Access
NGC 2915. II. A Dark Spiral Galaxy With A Blue Compact Dwarf Core
Abridged abstract: We present HI synthesis observations of the weak blue compact dwarf (BCD) galaxy NGC~2915. NGC~2915 has the HI properties of a late type spiral galaxy (Sd - Sm), including a double horn global profile, and HI spiral arms. The HI extends out to over five times the Holmberg radius. The optical counterpart corresponds to a central HI bar. The rotation curve is derived and fitted with a mass model consisting of a stellar disk, a neutral gas disk, and a dark matter (DM) halo. The DM halo dominates at nearly all radii. The total mass to blue light ratio is 76 within the last measured point, making NGC~2915 one of the darkest disk galaxies known. The core of the DM halo is unusually dense (rho_0 ~ 0.1, M_sun pc^{-3}) and compact (R_core approx 1 kpc). The neutral gas component, with mass M_g = 1.27x10^9 M_sun is probably more massive than the stellar component. Split and broad HI lines (line of sight velocity dispersion, sigma ~ 35 km/s) are seen in the central region. Pressure support is probably significant, and it is not clear whether the core is in equilibrium. Beyond the Holmberg radius, the average HI sigma is 8 km/s, which is normal for disk galaxies. NGC~2915 does not obey the Tully-Fisher (1977) relation, being underluminous by a factor of nine. A simple HI surface density threshold of about 10^{21} cm^{-2} adequately describes the location of current star formation. The HI properties are compared to "normal" disk galaxies and other BCDS.
Open AccessNGC 2915. II. A Dark Spiral Galaxy With A Blue Compact Dwarf Core
Abridged abstract: We present HI synthesis observations of the weak blue compact dwarf (BCD) galaxy NGC~2915. NGC~2915 has the HI properties of a late type spiral galaxy (Sd - Sm), including a double horn global profile, and HI spiral arms. The HI extends out to over five times the Holmberg radius. The optical counterpart corresponds to a central HI bar. The rotation curve is derived and fitted with a mass model consisting of a stellar disk, a neutral gas disk, and a dark matter (DM) halo. The DM halo dominates at nearly all radii. The total mass to blue light ratio is 76 within the last measured point, making NGC~2915 one of the darkest disk galaxies known. The core of the DM halo is unusually dense (rho_0 ~ 0.1, M_sun pc^{-3}) and compact (R_core approx 1 kpc). The neutral gas component, with mass M_g = 1.27x10^9 M_sun is probably more massive than the stellar component. Split and broad HI lines (line of sight velocity dispersion, sigma ~ 35 km/s) are seen in the central region. Pressure support is probably significant, and it is not clear whether the core is in equilibrium. Beyond the Holmberg radius, the average HI sigma is 8 km/s, which is normal for disk galaxies. NGC~2915 does not obey the Tully-Fisher (1977) relation, being underluminous by a factor of nine. A simple HI surface density threshold of about 10^{21} cm^{-2} adequately describes the location of current star formation. The HI properties are compared to "normal" disk galaxies and other BCDS.
- Open Access
Starbursts and Star Clusters in the Ultraviolet
Hubble Space Telescope ultraviolet (UV) images of nine starburst galaxies reveal them to be highly irregular, even after excluding compact sources (clusters and resolved stars). Most (7/9) are found to have a similar intrinsic effective surface brightnesses, suggesting that a negative feedback mechanism is setting an upper limit to the star formation rate per unit area. All starbursts in our sample contain UV bright star clusters indicating that cluster formation is an important mode of star formation in starbursts. On average about 20% of the UV luminosity comes from these clusters. The brightest clusters, or super star clusters (SSC), are preferentially found at the very heart of starbursts. The size of the nearest SSCs are consistent with those of Galactic globular clusters. The luminosity function of SSCs is well represented by a power law with a slope alpha ~ -2. There is a strong correlation between the far infrared excess and the UV spectral slope. The correlation is well modeled by a geometry where much of their dust is in a foreground screen near to the starburst, but not by a geometry of well mixed stars and dust.
Open AccessStarbursts and Star Clusters in the Ultraviolet
Hubble Space Telescope ultraviolet (UV) images of nine starburst galaxies reveal them to be highly irregular, even after excluding compact sources (clusters and resolved stars). Most (7/9) are found to have a similar intrinsic effective surface brightnesses, suggesting that a negative feedback mechanism is setting an upper limit to the star formation rate per unit area. All starbursts in our sample contain UV bright star clusters indicating that cluster formation is an important mode of star formation in starbursts. On average about 20% of the UV luminosity comes from these clusters. The brightest clusters, or super star clusters (SSC), are preferentially found at the very heart of starbursts. The size of the nearest SSCs are consistent with those of Galactic globular clusters. The luminosity function of SSCs is well represented by a power law with a slope alpha ~ -2. There is a strong correlation between the far infrared excess and the UV spectral slope. The correlation is well modeled by a geometry where much of their dust is in a foreground screen near to the starburst, but not by a geometry of well mixed stars and dust.