One of the largest X-ray surveys using the European Space Agency’s XMM-Newton space observatory has mapped nearly 12,000 X-ray sources across three large, prime regions of the sky. The X-ray sources represent active galactic nuclei and galaxy clusters, and the survey captures the growth of the supermassive black holes at the cores of these galaxies. This X-ray survey complements previous X-ray surveys, allowing the researchers to map active galactic nuclei in a wide range of cosmic environments. 

Currently available X-ray surveys are primarily either deep “pencil-beam” surveys covering a  very small part of the sky or shallow surveys covering large sky areas. Deep pencil-beam surveys can only sample active galactic nuclei in a limited cosmic volume, and they lack the ability to explore a wide dynamic range of cosmic environments. Shallow, wide-field surveys can sample a wider variety of environments but lack the sensitivity to detect the bulk of cosmic supermassive black hole growth. 

The new XMM-SERVS survey helps to fill the gap between deep pencil-beam X-ray surveys and shallow X-ray surveys over large sky areas. The XMM-SERVS survey provides medium-deep X ray coverage for three widely separated sky fields that have previously been studied at multiple wavelengths. Additionally, these regions have been selected as Deep-Drilling Fields of the  Legacy Survey of Space and Time (LSST) to be conducted by the Vera C. Rubin Observatory. The  Rubin Observatory is an 8.4-meter giant survey telescope located in north-central Chile, which is presently being constructed at a cost of more than $600 million. It represents one of the largest investments of the worldwide astronomical community in this decade. The LSST Deep Drilling Fields are sky regions where substantially more observations will be obtained compared to typical sky regions during the ten-year LSST survey, enabling new scientific discoveries. The  XMM-SERVS survey fields are also the sites of multiple other upcoming surveys at radio, submillimeter, infrared, and optical wavelengths. One of the XMM-SERVS survey fields is also among the Deep Fields of the €600-million space mission Euclid that will launch in 2022. Thus,  the X-ray coverage provided by XMM-SERVS has enormous legacy value in conjunction with these other rich datasets. 

The fields covered by the XMM-SERVS survey are the Wide Chandra Deep Field-South (W-CDF S), the European Large-Area Infrared Space Observatory S1 Survey (ELAIS-S1), and the XMM Newton Large-Scale Structure Survey (XMM-LSS). These sky areas, each spanning a few square  degrees, are already among the best-studied fields in the sky, and with the coming LSST and  other coverage they will be prime next-generation survey fields.  

“This survey represents key foundational work upon which, I suspect, hundreds of studies will  be built over the next decade or two,” said Brandt, Verne M. Willaman Professor of Astronomy  and Astrophysics and professor of physics at Penn State, and one of the leaders of the study.  “XMM-Newton was the best mission to gather these data, and we needed to invest a lot of  observation time for this study—with a total combined exposure of nearly 60 days—because it  will be so important for active galaxy studies, galaxy cluster studies, and for understanding  large-scale structures in the universe. It required a multiyear, multinational effort and it’s  incredibly gratifying to get it done. We are most grateful to the European Space Agency and  NASA for their long-term support of this work.” 

These X-ray observations will be invaluable to study the active galactic nuclei (i.e. black holes) and galaxy clusters (the largest cosmic structures bound together by gravity) detected by the MIGHTEE MeerKAT Large Survey Project in its ongoing mission to study the faint radio sky. The MIGHTEE MeerKAT Large Survey Project is led by University of the Western Cape’s Visiting Professor Matt Jarvis and Professor Russ Taylor, UCT/UWC/SKA South Africa Chair in Radio Astronomy.

Figure 2: XMM-Newton image of the 3.2-square-degree ELAIS-S1 field, which is about 15 times larger than the apparent size of the full moon (shown to scale at lower right). XMM SERVS provides a wide, sensitive X-ray view of this region.

Figure 3: XMM-Newton image of the 5.3-square-degree XMM-LSS field, which is about 25 times  larger than the apparent size of the full moon (shown to scale at lower right). XMM-LSS was the  first XMM-SERVS field to have been observed by XMM-Newton. Chien-Ting Chen, a former postdoctoral researcher at Penn State who is now an astronomer at USRA, led the work for this  field (see Chen et al. 2018, Mon. Not. Roy. Ast. Soc.). XMM-SERVS provides a wide, sensitive X ray view of this region. 

Reference: The XMM-SERVS survey: XMM-Newton point-source catalogs for the W-CDF-S and ELAIS-S1 fields
Q. Ni, W. N. Brandt, C.-T. Chen, B. Luo, K. Nyland, G. Yang, F. Zou, J. Aird, D. M. Alexander, F. E. Bauer, M. Lacy, B. D. Lehmer, L. Mallick, M. Salvato, D. P. Schneider, P. Tozzi, I. Traulsen, M. Vaccari, C. Vignali, F. Vito, Y. Xue, M. Banerji, K. Chow, A. Comastri, A. Del Moro, R. Gilli, J. Mullaney, M. Paolillo, A. Schwope, O. Shemmer, M. Sun, J. D. Timlin, J. R. Trump

Article including images originally sourced from: New X-ray map reveals growing supermassive black holes in next-gen survey fields