The Dark Energy Spectroscopic Instrument (DESI) was designed to conduct a survey covering 14,000 deg 2 over 5 yr to constrain the cosmic expansion history through precise measurements of baryon acoustic oscillations (BAO). The scientific program for DESI was evaluated during a 5 month survey validation (SV) campaign before beginning full operations

Extragalactic fast X-ray transients (FXTs) are a class of soft (0.3-10 keV) X-ray transients lasting a few hundred seconds to several hours. Several progenitor mechanisms have been suggested to produce FXTs, including supernova shock breakouts, binary neutron star mergers, or tidal disruptions involving an intermediate-mass black hole and a white

A variety of Prehistoric dry-stone monuments are ubiquitous in Western Sahara, a region delimited by the boundaries of the former Spanish colony. With either burial or ritual functions, these monuments are spread throughout the Sahara Desert creating sacred landscapes and housing the memory of millennia of occupation. Previous research has explored

Almost dark galaxies are objects that have eluded detection by traditional surveys such as the Sloan Digital Sky Survey (SDSS). The low surface brightness of these galaxies (μ r(0) > 26 mag arcsec −2), and hence their low surface stellar mass density (a few solar masses per pc 2 or less), suggest that the energy density released by baryonic

The chromatic contamination that arises from photospheric heterogeneities, e.g., spots and faculae on the host star presents a significant noise source for exoplanet transmission spectra. If this contamination is not corrected for, it can introduce substantial bias in our analysis of the planetary atmosphere. We utilize two stellar models of

We compare a method for inferring the photospheric vector magnetic field using only spectroscopy to a conventional method based on polarimetry. The magnetic field strength B and inclination angle can be inferred from the Zeeman splitting using only Stokes I. We applied this method to a sunspot observed with the Vacuum Tower Telescope and compared