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

Context. The usual approach to classify the ionizing source using optical spectroscopy is based on the use of diagnostic diagrams that compare the relative strength of pairs of collisitional metallic lines (e.g., [O III] and [N II]) to recombination hydrogen lines (e.g., Hβ and Hα). Despite it having been accepted as the standard procedure, it

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

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

We report on the precise radial velocity follow-up of TOI-544 (HD 290498), a bright K star (V = 10.8), which hosts a small transiting planet recently discovered by the Transiting Exoplanet Survey Satellite (TESS). We collected 122 high-resolution High Accuracy Radial velocity Planet Searcher (HARPS) and HARPS-N spectra to spectroscopically confirm

We report on the precise radial velocity follow-up of TOI-544 (HD 290498), a bright K star (V = 10.8), which hosts a small transiting planet recently discovered by the Transiting Exoplanet Survey Satellite (TESS). We collected 122 high-resolution High Accuracy Radial velocity Planet Searcher (HARPS) and HARPS-N spectra to spectroscopically confirm