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We present high signal-to-noise spectrophotometric observations of seven luminous HII galaxies. The observations have been made with the use of a double-arm spectrograph which provides spectra with a wide wavelength coverage, from 3400 to…

We present near-IR VLT/ISAAC and mid-IR Spitzer/IRS spectroscopy of the young massive cluster in the W31 star-forming region. H-band spectroscopy provides refined classifications for four cluster members O stars with respect to Blum et al.…

Solar and Stellar Astrophysics · Physics 2015-05-14 JP Furness , PA Crowther , PW Morris , CL Barbosa , RD Blum , PS Conti , SD van Dyk

We study the impact of deviations from the Kennicutt-Schmidt relation (quantified by the `burstiness' parameter $\kappa_s$), gas metallicity ($Z$), and density ($n$) on the observed [OIII]88$\mu$m/[CII]158$\mu$m surface brightness ratios…

Astrophysics of Galaxies · Physics 2021-06-11 L. Vallini , A. Ferrara , A. Pallottini , S. Carniani , S. Gallerani

Starbursts and substantial variations in the star formation histories are a common phenomenon in galaxies. We study the stability properties of isolated star-forming dwarf galaxies with the aim of identifying starburst modes. The impact of…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 Christian Theis , Joachim Koeppen

Herbig Ae/Be stars are intermediate-mass pre-main sequence stars undergoing accretion through their circumstellar disk. The optical and infrared (IR) spectra of HAeBe stars show HI emission lines belonging to Balmer, Paschen and Brackett…

Solar and Stellar Astrophysics · Physics 2023-06-28 B. Shridharan , Blesson Mathew , R. Arun , T. B. Cysil

We present evolutionary stellar population synthesis models to predict the spectrum of a single-metallicity stellar population, with a spectral sampling of 0.3 A in five spectral regions between 3700 and 5000 A. The models, which are…

Astrophysics · Physics 2009-10-31 Rosa M. Gonzalez Delgado , Claus leitherer , Timothy Heckman

We present results on the emission-line properties of z=1.4-7.5 star-forming galaxies in the Assembly of Ultradeep Rest-optical Observations Revealing Astrophysics (AURORA) Cycle 1 JWST/NIRSpec program. Based on its depth, continuous…

Supernovae play an integral role in the feedback of processed material into the ISM of galaxies and are responsible for much of the chemical enrichment of the universe. The rate of supernovae can also reveal the star formation histories.…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 M. J. F. Rosenberg , P. P. van der Werf , F. P. Israel

In systems undergoing starbursts the evolution of the young stellar population is expected to drive changes in the emission line properties. This evolution is usually studied theoretically, with a combination of evolutionary synthesis…

We present SHARC-2 350 micron data on 20 luminous z ~ 2 starbursts with S(1.2mm) > 2 mJy from the Spitzer-selected samples of Lonsdale et al. and Fiolet et al. All the sources were detected, with S(350um) > 25 mJy for 18 of them. With the…

Cosmology and Nongalactic Astrophysics · Physics 2010-06-09 A. Kovács , A. Omont , A. Beelen , C. Lonsdale , M. Polletta , N. Fiolet , T. R. Greve , C. Borys , P. Cox , C. De Breuck , H. Dole , C. D. Dowell , D. Farrah , G. Lagache , K. M. Menten , T. A. Bell , F. Owen

The oxygen abundance gradients among nebular emission line regions in spiral galaxies have been used as important constraints for models of chemical evolution. We present the largest ever full-wavelength optical spectroscopic sample of…

Cosmology and Nongalactic Astrophysics · Physics 2013-10-17 Nathan Sanders , Nelson Caldwell , Jonathan McDowell , Paul Harding

We present optical spectroscopy of a sample of metal-rich extragalactic HII regions in the spiral galaxies M83, NGC 3351 and NGC 6384, including a number of circumnuclear HII regions (hot spots). Different age estimators (equivalent width…

Astrophysics · Physics 2009-11-07 Fabio Bresolin , Robert C. Kennicutt

Optical emission-line ratios are traditionally used to estimate gas metallicities from observed galaxy spectra. While such estimators have been calibrated primarily at low redshift, they are commonly used to study high-redshift galaxies,…

Astrophysics of Galaxies · Physics 2023-05-09 Michaela Hirschmann , Stephane Charlot , Rachel S. Somerville

Context. The increased detection rate of Fast Radio Bursts (FRBs) makes it likely to get samples of sizes $\mathcal{O}(10^2)$ to $\mathcal{O}(10^3)$ in the near future. Because of their extragalactic origin can help us in understanding the…

High Energy Astrophysical Phenomena · Physics 2021-05-28 Albert Wai Kit Lau , Ayan Mitra , Mehdi Shafiee , George Smoot

We investigate the stellar and nebular properties of 9 H II regions in the spiral galaxy M101 with far-ultraviolet (FUV; ~900-2000 \r{A}) and optical (~3200-10000 \r{A}) spectra. We detect significant C III] 1907,1909 nebular emission in 7…

The behavior of the aromatic features as a function of metallicity/radiation field hardness in M101 HII regions and starburst galaxies is investigated using Spitzer/IRS spectra. These spectra reveal that the 6.2, 7.8+8.6, and 11.3 micron…

Astrophysics · Physics 2007-05-23 Karl D. Gordon , C. W. Engelbracht , J. -D. T. Smith , G. H. Rieke , K. A. Misselt

We present a multiwavelength study of star formation within the nearby M101 Group, including new deep H$\alpha$ imaging of M101 and its two companions. We perform a statistical analysis of the H$\alpha$ to FUV flux ratios in HII regions…

Astrophysics of Galaxies · Physics 2017-12-27 Aaron E. Watkins , J. Christopher Mihos , Paul Harding

We present near-infrared spectra for a sample of galaxies with ambiguous optical emission line ratios. These galaxies fall between starbursts and Seyferts in the usual optical diagnostic diagrams. We find a similar result with the…

Astrophysics · Physics 2009-10-31 Tanya L. Hill , Charlene A. Heisler , Ralph Sutherland , Richard W. Hunstead

Recently, mid-infrared instruments have become available on several large ground-based telescopes, resulting in data sets with unprecedented spatial resolution at these long wavelengths. In this paper we examine 'ground-based-only'…

Astrophysics · Physics 2009-11-13 Leonie Snijders , Lisa J. Kewley , Paul P. van der Werf