Search

Your search keyword '"van Dokkum, P. G."' showing total 4 results
Start Over Author "van Dokkum, P. G." Journal nature
4 results on '"van Dokkum, P. G."'

1. A massive, quiescent, population II galaxy at a redshift of 2.1

Author

Kriek, Mariska, Conroy, Charlie, van Dokkum, Pieter G, Shapley, Alice E, Choi, Jieun, Reddy, Naveen A, Siana, Brian, van de Voort, Freeke, Coil, Alison L, and Mobasher, Bahram

Subjects
Astronomical Sciences, Physical Sciences, astro-ph.GA, astro-ph.CO, General Science & Technology
Abstract

Unlike spiral galaxies such as the Milky Way, the majority of the stars in massive elliptical galaxies were formed in a short period early in the history of the Universe. The duration of this formation period can be measured using the ratio of magnesium to iron abundance ([Mg/Fe]) in spectra, which reflects the relative enrichment by core-collapse and type Ia supernovae. For local galaxies, [Mg/Fe] probes the combined formation history of all stars currently in the galaxy, including younger and metal-poor stars that were added during late-time mergers. Therefore, to directly constrain the initial star-formation period, we must study galaxies at earlier epochs. The most distant galaxy for which [Mg/Fe] had previously been measured is at a redshift of z ≈ 1.4, with [Mg/Fe] = . A slightly earlier epoch (z ≈ 1.6) was probed by combining the spectra of 24 massive quiescent galaxies, yielding an average [Mg/Fe] = 0.31 ± 0.12 (ref. 7). However, the relatively low signal-to-noise ratio of the data and the use of index analysis techniques for both of these studies resulted in measurement errors that are too large to allow us to form strong conclusions. Deeper spectra at even earlier epochs in combination with analysis techniques based on full spectral fitting are required to precisely measure the abundance pattern shortly after the major star-forming phase (z > 2). Here we report a measurement of [Mg/Fe] for a massive quiescent galaxy at a redshift of z = 2.1, when the Universe was three billion years old. With [Mg/Fe] = 0.59 ± 0.11, this galaxy is the most Mg-enhanced massive galaxy found so far, having twice the Mg enhancement of similar-mass galaxies today. The abundance pattern of the galaxy is consistent with enrichment exclusively by core-collapse supernovae and with a star-formation timescale of 0.1 to 0.5 billion years-characteristics that are similar to population II stars in the Milky Way. With an average past star-formation rate of 600 to 3,000 solar masses per year, this galaxy was among the most vigorous star-forming galaxies in the Universe.

Published
2016

3. The afterglow, redshift and extreme energetics of the gamma-ray burst of 23 January 1999

Author

Kulkarni, S. R., Djorgovski, S. G., Odewahn, S. C., Bloom, J. S., Gal, R. R., Koresko, C. D., Harrison, F. A., Lubin, L. M., Armus, L., Sari, R., Illingworth, G. D., Kelson, D. D., Magee, D. K., van Dokkum, P. G., Frail, D. A., Mulchaey, J. S., Malkan, M. A., McClean, I. S., Teplitz, H. I., Koerner, D., Kirkpatrick, D., Kobayashi, N., Yadigaroglu, I.-A., Halpern, J., Piran, T., Goodrich, R. W., Chaffee, F. H., Feroci, M., and Costa, E.

Published
1999

4. Quenching of star formation from a lack of inflowing gas to galaxies

Author

Whitaker, Katherine E., Williams, Christina C., Mowla, Lamiya, Spilker, Justin S., Toft, Sune, Narayanan, Desika, Pope, Alexandra, Magdis, Georgios E., van Dokkum, Pieter G., Akhshik, Mohammad, Bezanson, Rachel, Brammer, Gabriel B., Leja, Joel, Man, Allison, Nelson, Erica J., Richard, Johan, Pacifici, Camilla, Sharon, Keren, and Valentino, Francesco

Abstract

Star formation in half of massive galaxies was quenched by the time the Universe was 3 billion years old1. Very low amounts of molecular gas seem to be responsible for this, at least in some cases2–7, although morphological gas stabilization, shock heating or activity associated with accretion onto a central supermassive black hole are invoked in other cases8–11. Recent studies of quenching by gas depletion have been based on upper limits that are insufficiently sensitive to determine this robustly2–7, or stacked emission with its problems of averaging8,9. Here we report 1.3 mm observations of dust emission from 6 strongly lensed galaxies where star formation has been quenched, with magnifications of up to a factor of 30. Four of the six galaxies are undetected in dust emission, with an estimated upper limit on the dust mass of 0.0001 times the stellar mass, and by proxy (assuming a Milky Way molecular gas-to-dust ratio) 0.01 times the stellar mass in molecular gas. This is two orders of magnitude less molecular gas per unit stellar mass than seen in star forming galaxies at similar redshifts12–14. It remains difficult to extrapolate from these small samples, but these observations establish that gas depletion is responsible for a cessation of star formation in some fraction of high-redshift galaxies.

Published
2021
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results