The Eighteenth Data Release of the Sloan Digital Sky Surveys: Targeting and First Spectra from SDSS-V

Abstract

The eighteenth data release (DR18) of the Sloan Digital Sky Survey (SDSS) is the first one for SDSS-V, the fifth generation of the survey. SDSS-V comprises three primary scientific programs or “Mappers”: the Milky Way Mapper (MWM), the Black Hole Mapper (BHM), and the Local Volume Mapper. This data release contains extensive targeting information for the two multiobject spectroscopy programs (MWM and BHM), including input catalogs and selection functions for their numerous scientific objectives. We describe the production of the targeting databases and their calibration and scientifically focused components. DR18 also includes ∼25,000 new SDSS spectra and supplemental information for X-ray sources identified by eROSITA in its eFEDS field. We present updates to some of the SDSS software pipelines and preview changes anticipated for DR19. We also describe three value-added catalogs (VACs) based on SDSS-IV data that have been published since DR17, and one VAC based on the SDSS-V data in the eFEDS field.

Probing Cosmology with Baryon Acoustic Oscillations Using Gravitational Waves

“…Therefore, combining the GW-BAO measurements and galaxy-BAO measurements shall provide the combined constraints on parameters Ω m0 and H 0 . We expect that current and future spectroscopic surveys such as SDSS (Almeida et al 2023), Euclid (Laureijs et al 2011), and Vera C. Rubin Observatory (Ivezić 2019) will provide more robust BAO measurements by the time 3G detectors are operational. However, in this study, we use current galaxy-BAO measurements and combine them with projected GW-BAO measurements from the simulations done for 3G GW detectors to get conservative estimates of the constraining power of the combination of the data.…”

A Markedly Expanded Sample of Candidate X-Ray-emitting Isolated Neutron Stars

“…Attempts to match optical counterparts to a large fraction of RASS X-ray sources extend back decades (e.g., Bade et al 1998;Rutledge et al 2000;Zickgraf et al 2003;Flesch & Hardcastle 2004); however, the number of secure RASS X-ray-optical identifications with confirming optical spectroscopy or other multiwavelength affirmations is still often measured in the tens of thousands (Comparat et al 2020). That so many X-ray sources are known, and that their X-ray error circles are often large enough to contain multiple potential optical counterparts, renders a need for extensive coordinated wide-field optical (e.g., SDSS) and X-ray [e.g., RASS; Comparat et al 2020;and eROSITA Kollmeier et al 2019;Almeida et al 2023] studies, in order to obtain secure counterpart identifications for the remainder.…”

BASS. XXXV. The M BH–σ* Relation of 105 Month Swift-BAT Type 1 AGNs

“…While the large size and high completeness of the sample used for our analysis present significant progress in studying the M BH -σ å relation, and extinction effects, in low-redshift AGNs, it also highlights areas where more progress in terms of the census of low-redshift AGNs and their hosts is direly needed. Specifically, new and upcoming X-ray missions, such as the extended Roentgen Survey with an Imaging Telescope Array on board the Spectrum-Roentgen-Gamma (Predehl et al 2021), Advanced Telescope for High Energy Astrophysics (Nandra et al 2013), and the Advanced X-ray Imaging Satellite (Mushotzky 2018), will greatly improve our ability to construct yet larger, more complete AGN samples at high redshift for which homogeneous and robust spectral analysis can be obtained, to deduce key properties both in the X-ray and also in optical regimes thanks to spectroscopic surveys such as SDSS-V (Kollmeier et al 2017;Almeida et al 2023) or the 4 m Multi-Object Spectroscopic Telescope (de Jong et al 2016). This will further help to break any outstanding degeneracies between AGN luminosities, BH masses, accretion rates and states, and host galaxy types and properties.…”