BHM Data - SDSS

Previous SDSS data most relevant to BHM

Please also see earlier SDSS data releases, including DR16, DR17, and DR18 which e.g., include BHM relevant science and data, from other earlier SDSS programs and releases:

eBOSS sub- or ancillary-programs on SDSS-IV SPIDERS , TDSS, and reverberation mapping (including optical follow of ROSAT X-ray sources, and time-domain repeat quasar spectroscopy).
The DR16 Quasar Catalog (Lyke et al., 2020), which is an important underlying targeting catalog for some BHM repeat quasar spectroscopy, especially BHM/AQMES.
SDSS-IV eFEDS plate data in DR17 which provided initial BOSS spectroscopy on 7 plates in the eFEDS region; and SDSS-V eFEDS plate data in DR18 which extended BOSS (joint with APOGEE) spectra to 37 plates, for (mostly) X-ray selected targets in the eROSITA eFEDS field.

This image has an empty alt attribute; its file name is eFEDS_SDSS_map_plates_DR16_Mar2020_SDSSV_spectra-2-1024x512.png — BHM/SPIDERS eFEDS-followup in previous data releases (through DR18): The SRG/eROSITA mission completed a mini-X-ray survey of a 140 sq. deg. region (called eFEDS; Brunner et al. 2022) in 2019. Starting in SDSS-IV & completed during SDSS-V, BOSS spectra were extended to encompass ~12,000 counterparts of eFEDS X-ray sources, including quasars/AGN (which dominate), clusters of galaxies, & Galactic X-ray sources. Such SDSS-V eFEDS spectra were a major component of SDSS DR18; for additional details, see Almeida et al. (2023); Aydar et al. (2025).

New data for BHM in DR19

BOSS spectra

SDSS DR19 includes the release of a total of ~380,000 BOSS spectra for ~120,000 distinct objects primarily targeted for spectroscopy by BHM, an order of magnitude expansion vs. DR18. These extend across nearly the full suite of main BHM science programs. DR19 emphasizes especially northern and equatorial fields, and with BOSS optical spectra taken for AQMES, RM, SPIDERS, CSC, and BHM-related ancillary science programs from APO (up to July 2023) . Additional more-detailed information on spectra, spectroscopic parameters, and targeting aspects in DR19 may also be found in links from the right hand menu.

Distribution on the sky in RA and Dec for ~120k distinct objects encompassed by the DR19 release, targeted primarily for optical BOSS spectroscopy by BHM. Black Hole Mapper often takes multiple BOSS spectra of the same object/target, to achieve adequate S/N for the intended science, and/or for spectroscopic time-domain studies. A total of ~380k spectra of the ~120k distinct BHM objects are included, and the color coding (logarithmically) depicts the number (per object) of such DR19 spectra for each of the ~120k BHM targets.

Distribution of apparent magnitudes and redshifts (as provided by the spectroscopic pipeline) for the same ~120k BHM objects,with DR19 BOSS optical spectroscopy. The color coding again depicts the number of spectra (per object) released in DR19 for each of these BHM spectroscopic targets (e.g., sometimes indicative of time-domain spectroscopic monitoring of the target). DR19 represents an order of magnitude expansion in BHM spectroscopic targets encompassed, and in the numbers of spectra released *vs.* DR18; these spectra span nearly the full set of BHM science programs.

Sky density of BHM targets having at least one BOSS spectrum in DR19. Here we include all targets that are a member of any BHM core or filler carton. We do not include openfiber cartons.

Value Added Catalogues

As with previous SDSS data releases, DR19 also includes a number of Value Added Catalogs (VACs). These VACs, including several associated with BHM projects, provide more detailed and/or more scientifically focused views of the spectroscopic data.

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