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New observations of the quasar HE0515$-$4414 have been made using the HARPS spectrograph on the ESO 3.6m telescope, aided by the Laser Frequency Comb (LFC). We present three important advances for $\alpha$ measurements in quasar absorption…

Cosmology and Nongalactic Astrophysics · Physics 2021-03-08 Dinko Milaković , Chung-Chi Lee , Robert F. Carswell , John K. Webb , Paolo Molaro , Luca Pasquini

We present models that predict spectra of old- and intermediate-aged stellar populations at 2.51\AA\ (FWHM) with varying [\alpha/Fe] abundance. The models are based on the MILES library and on corrections from theoretical stellar spectra.…

We demonstrate the capability of block-copolymer templating to tune the refractive indices of functional oxides over a broad range by structuring materials on the 20-1000 atoms scale, with simple one-pot synthesis. The presented method is…

Mesoscale and Nanoscale Physics · Physics 2020-04-08 Jacob Poole , Aidong Yan , Paul Ohodnicki , Kevin Chen

Observations of extragalactic objects need to be corrected for Galactic absorption and this is often accomplished by using the measured 21 cm HI column. However, within the beam of the radio telescope there are variations in the HI column…

Astrophysics · Physics 2009-11-10 Joel N. Bregman , Megan C. Novicki , Jessica E. Krick , John S. Arabadjis

Detailed Monte Carlo Inversion analysis of the spectral lines from three Lyman limit systems (LLS) [N(HI) > 10^{17} cm^-2] and nine lower N(HI) systems [2 10^{14} < N(HI) < 2 10^{16} cm^-2] observed in the VLT/UVES spectra of Q0347-3819 (in…

Determining accurate effective temperatures of stars buried in the dust-obscured Galactic regions is extremely difficult from photometry. Fortunately, high-resolution infrared spectroscopy is a powerful tool for determining the temperatures…

UV absorption line indices trace both chemical enrichment and star formation histories in high-redshift galaxies, yet their reliability as tracers of stellar metallicity (\(Z_\star\)) remains uncertain. In this study, we combine synthetic…

We present a new technique for the determination of the low-mass slope ($\alpha_1$; $M_* < 0.5 M_{\odot}$) of the present day stellar mass function (PDMF) using the pixel space fitting of integrated light spectra. It can be used to…

Instrumentation and Methods for Astrophysics · Physics 2015-06-15 Nikolay Podorvanyuk , Igor Chilingarian , Ivan Katkov

At visible and infrared frequencies, metals show tantalizing promise for strong subwavelength resonances, but material loss typically dampens the response. We derive fundamental limits to the optical response of absorptive systems, bounding…

We present a new database of absorption and emission-line measurements based on the entire spectral atlas from the Sloan Digital Sky Survey (SDSS) 7th data release of galaxies within a redshift of 0.2. Our work makes use of the publicly…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 Kyuseok Oh , Marc Sarzi , Kevin Schawinski , Sukyoung K. Yi

We present a grid of synthetic profiles of stellar H Balmer and HeI lines at optical wavelengths with a sampling of 0.3 A. The grid spans a range of effective temperature 4000 K < Teff < 50000 K, and gravity 0.0 < log g < 5.0 at solar…

Astrophysics · Physics 2009-10-31 Rosa M. Gonzalez Delgado , Claus Leitherer

We present results from a search for 21 cm associated HI absorption in a sample of 29 radio sources selected from the Australia Telescope 20 GHz survey. Observations were conducted using the Australia Telescope Compact Array Broadband…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 J. R. Allison , S. J. Curran , B. H. C. Emonts , K. Gareb , E. K. Mahony , S. Reeves , E. M. Sadler , A. Tanna , M. T. Whiting , M. A. Zwaan

With the aim of building a data-set of spectral properties of well studied early-type galaxies showing emission lines, we present intermediate resolution spectra of 50 galaxies in the nearby Universe. The sample, which covers several of the…

Astrophysics · Physics 2009-11-10 R. Rampazzo , F. Annibali , A. Bressan , M. Longhetti , F. Padoan , W. W. Zeilinger

A theoretical model of the influence of detection bandwidth properties on observed line shapes in laser absorption spectroscopy is described. The model predicts artificial frequency shifts, extra broadenings and line asymmetries which must…

We measured the equivalent width of a large set of near-infrared (NIR, 0.8--2.4$ \ \mu$m) line-strength indices in the XShooter medium-resolution spectra of the central regions of 14 galaxies. We found that two aluminum indices Al at 1.31…

We present the single stellar population (SSP) synthesis results of our new synthetic stellar atmosphere models library with a spectral sampling of 0.3 A, covering the wavelength range from 3000 A to 7000 A for a wide range of metallicities…

The near-infrared emission lines of Fe$^{+}$ at 1.257, 1.321, and 1.644 $\mu$m share the same upper level; their ratios can then be exploited to derive the extinction to a line emitting region once the relevant spontaneous emission…

Instrumentation and Methods for Astrophysics · Physics 2016-08-10 Tommaso Pecchioli , Nicoletta Sanna , Fabrizio Massi , Ernesto Oliva

We have performed first principles electron-correlated calculations employing large basis sets to optimize the geometries, and to compute linear optical absorption spectra of various low-lying conformers of silicon hydrides:…

Atomic and Molecular Clusters · Physics 2019-10-16 Pritam Bhattacharyya , Deepak Kumar Rai , Alok Shukla

We used moderately high-resolution, high S/N spectra to study the chemical composition of 10 field ab-type RR Lyrae stars. A new temperature scale was determined from literature Infrared Flux Method measures of subdwarfs and the Kurucz…

Astrophysics · Physics 2009-11-24 G. Clementini , E. Carretta , R. Gratton , R. Merighi , J. R. Mould , J. K. McCarthy

Astronomical spectrographs require frequency calibration through sources like hollow-cathode lamps or absorption-gas cells. Laser frequency combs (LFCs) provide highest accuracy but are facing operational challenges. We aim to provide a…

Instrumentation and Methods for Astrophysics · Physics 2024-09-05 Ansgar Reiners , Michael Debus , Sebastian Schäfer , Eberhard Tiemann , Mathias Zechmeister
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