Supermassive Black Hole Studies with the LSST - 2019 June

This is a recording of a talk titled "Supermassive Black Hole Studies with the LSST". This talk was originally given on 2019 June 26 at "Quasars in Cosmology", which was Session S2 of the 2019 European Week of Astronomy and Space Science held in Lyon, France (the talk here was recorded separately, and is longer and more detailed since I did not have the time constraint I had in France). The speaker is Prof. W.N. Brandt from the Department of Astronomy & Astrophysics at Penn State University, and the talk is being given on behalf of the LSST Science Collaboration on Active Galactic Nuclei (AGN). The talk has overlap with some of my previous LSST AGN talks on YouTube, but it is substantially updated and supersedes those previous talks. The talk abstract is the following: The LSST will enable studies of the growing supermassive black holes (SMBHs) in active galactic nuclei (AGNs), including luminous quasars, on a truly massive scale. After a brief review of the LSST surveys from an AGN/quasar perspective, I will describe the selection of tens of millions of AGNs/quasars using LSST plus multiwavelength data. I will then highlight examples of exciting relevant LSST science investigations including massive AGN/quasar variability studies, transient SMBH fueling events, and high-redshift AGNs/quasars. I will end by describing the details of the LSST AGN Science Collaboration, its ongoing activities, and its future plans. The slides for this talk are available at https://agn.science.lsst.org/?q=docum... Some more details about the LSST AGN Science Collaboration and relevant topics can be found at https://agn.science.lsst.org/ and http://personal.psu.edu/wnb3/xmmservs... A more detailed talk outline is the following: The surveys conducted by LSST will include a main survey over ~ 18000 square degrees, Deep Drilling Fields (DDFs), and selected mini-surveys. The details of all these surveys are presently being decided via an extensive survey strategy optimization process, which has included substantial community input and will run until at least 2021-2022. It is expected that the main survey will take 80-90% of the LSST time with the mini-surveys, including the DDFs, using the rest. Exciting AGN science will be done with most of the LSST surveys, and the AGN SC has been actively participating in the optimization process via white papers and other inputs. AGNs can be selected from the LSST data alone using multi-color selection, variability, and astrometric information. Estimates indicate that these selection approaches should find about 10 million AGNs. Moreover, as expected from the highly multiwavelength nature of AGN emission, AGN selection can be substantially further improved by combining LSST data with radio (e.g., ASKAP, MeerKAT, SKA), infrared (e.g., VISTA, Spitzer, Euclid, WFIRST), and X-ray (e.g., Chandra, XMM-Newton, eROSITA, Athena) data. Current estimates indicate that all of these data together should allow the selection of 20-50 million or more AGNs. The LSST data will enable manifold exciting AGN science investigations. Many of these are described in Chapter 10 of the LSST Science Book and on the Web page for the AGN SC mentioned above. In this talk, I focused on three specific topics. First, I described prospects for LSST AGN variability studies, including general luminosity/spectral variability with massive samples, LSST plus time-domain spectroscopic investigations, probes of accretion-disk structure via continuum reverberation mapping and microlensing, and variability of small-separation binary SMBHs. Second, I discussed expected LSST discoveries of transient fueling events of dormant SMBHs by the tidal disruption and accretion of stars, planets, and gas clouds. Third, I discussed prospects for the discovery of high-redshift AGNs with LSST data alone (reaching z ~ 7.5) and via the combination of LSST, Euclid, and WFIRST data (reaching z ~ 9+). The LSST AGN SC currently has 57 members. These are mostly from the USA, Chile, and the UK with some representation from mainland Europe, Australia, and Canada. There have been a few SC meetings or other gatherings to date where AGN science, roadmapping/prioritization, and general planning have been discussed. The AGN SC has generally been working as a loose confederation. It would ideally become a more formal and rigorously operating collaboration, but further organization and activity has been challenging owing to, e.g., an almost total lack of funding for LSST science preparation in the USA. Given the funding challenges, some AGN SC members have been proceeding via a "bootstrapping" approach, working on surveys that build toward LSST and also provide immediately publishable scientific results (e.g., deep-field surveys, SDSS, Pan-STARRS, DES, HSC). Other AGN SC members have been gathering critical multiwavelength data for LSST work as well as nearer term science, particularly with Spitzer and XMM-Newton in the LSST DDFs.