HST Low Resolution Stellar Library

Abstract

Hubble Space Telescope's (HST) Space Telescope Imaging Spectrograph (STIS) targeted 556 stars in a long-running program called Next Generation Spectral Library (NGSL) via proposals GO9088, GO9786, GO10222, and GO13776. Exposures through three low resolution gratings provide wavelength coverage from 0.2 $<\lambda <$ 1 $\mu$m at $\lambda /\Delta \lambda \sim$ 1000, providing unique coverage in the ultraviolet (UV). The UV grating (G230LB) scatters red light and this results in unwanted flux that becomes especially troubling for cool stars. We applied scattered light corrections based on \cite{2022stis.rept....5W} and flux corrections arising from pointing errors relative to the center of the 0\farcs2 slit. We present 514 fully reduced spectra, fluxed, dereddened, and cross-correlated to zero velocity. Because of the broad spectral range, we can simultaneously study H$\alpha$ and Mg II $\lambda$2800, indicators of chromospheric activity. Their behaviours are decoupled. Besides three cool dwarfs and one giant with mild flares in H$\alpha$, only Be stars show strong H$\alpha$ emission. Mg2800 emission, however, strongly anti-correlates with temperature such that warm stars show absorption and stars cooler than $5000\mathrm{K}$ universally show chromospheric emission regardless of dwarf/giant status or metallicity. Transformed to Mg2800 flux emerging from the stellar surface, we find a correlation with temperature with approximately symmetric astrophysical scatter, in contrast to other workers who find a basal level with asymmetric scatter to strong values. Unsurprisingly, we confirm that Mg2800 activity is variable.

arXiv comment19 pages, 20 figures, 3 tables. Full version of table 3 is available online at https://archive.stsci.edu/hlsp/lowlib

References in corpus (43)

• Stellar population synthesis at the resolution of 2003
• Correcting for the Effects of Interstellar Extinction
• The SIMBAD astronomical database
• MILES: A Medium resolution INT Library of Empirical Spectra
• Passively Evolving Early-type Galaxies at 1.4<z<2.5 in the Hubble Ultra Deep Field
• An updated MILES stellar library and stellar population models
• A standard stellar library for evolutionary synthesis: I. Calibration of theoretical spectra
• The Indo-U.S. Library of Coude Feed Stellar Spectra
• A standard stellar library for evolutionary synthesis: II. The M dwarf extension
• UV-extended E-MILES stellar population models: young components in massive early-type galaxies
• The Ultraviolet Spectrum of MS 1512-cB58: An Insight into Lyman Break Galaxies
• A three-dimensional Galactic extinction model
• The Absolute Magnitude of the Sun in Several Filters
• Evolutionary synthesis of galaxies at high spectral resolution with the code PEGASE-HR
• MIUSCAT: extended MILES spectral coverage. I. Stellar populations synthesis models
• An Empirical UBVRIJHK Color-Temperature Calibration for Stars
• Long-term magnetic activity of a sample of M-dwarf stars from the HARPS program I. Comparison of activity indices
• Coude-feed stellar spectral library - atmospheric parameters
• The Ages and Abundances of the M87 Globular Clusters
• Fluxes in Hαand Ca II H and K for a sample of Southern stars
• Chromospheric activity as age indicator
• Stellar population models in the UV: I. Characterisation of the New Generation Stellar Library
• No Such Thing as a Simple Flare: Substructure and QPPs Observed in a Statistical Sample of 20 Second Cadence TESS Flares
• Magnetic activity and differential rotation in the young Sun-like stars KIC 7985370 and KIC 7765135
• Evolutionary Synthesis Of Simple Stellar Populations
• On the long-term correlation between the flux in the Ca II H & K and Halpha lines for FGK stars
• Modelling simple stellar populations in the near-ultraviolet to near-infrared with the X-shooter Spectral Library (XSL)
• Hubble Space Telescope WFC3 Grism Spectroscopy and Imaging of a Growing Compact Galaxy at z=1.9
• Mg II h + k emission lines as stellar activity indicators of main sequence F-K stars
• The Infrared Telescope Facility (IRTF) spectral library: spectral diagnostics for cool stars
• GALExtin: An alternative online tool to determine the interstellar extinction in the Milky Way
• The Basal Chromospheric Mg II h+k Flux of Evolved Stars: Probing the Energy Dissipation of Giant Chromospheres
• Linking chromospheric activity and magnetic field properties for late-type dwarf stars
• Synthetic Mid-UV Spectroscopic Indices of Stars
• Relationship between Ca and H$\alpha$ chromospheric emission in F-G-K stars: indication of stellar filaments?
• The high velocity stars in the Local Stellar Halo from Gaia and LAMOST
• Rotation and magnetism in intermediate mass stars
• HST Observations of Chromospheres in Metal Deficient Field Giants
• On the Wilson-Bappu relationship in the Mg II k line
• BaSeL: a library of synthetic spectra and colours for GAIA
• NH and Mg Index Trends in Elliptical Galaxies
• Hot Star Extension to the Hubble Space Telescope Stellar Spectral Library
• Individual element sensitivity for stellar evolutionary isochrones

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