I will briefly review what X-ray surveys and their multiwavelength follow-up have revealed about the sources constituting the cosmic X-ray background (CXRB), focusing on results from the past 25 years from missions including Chandra, Einstein Probe, INTEGRAL, NuSTAR, SRG, Swift, and XMM-Newton. I will first detail the identification, classification, and basic nature of the extragalactic...
Surveys of the radio sky have a long history, dating back to the very early days of radio astronomy. These early surveys provided crucial input to our understanding of both cosmology and the AGN/quasar population. As the field of radio astronomy has evolved so to have survey techniques, resulting in the current "Golden Age" of radio surveys. Wide-field surveys today cover frequency ranges from...
After more than two years of scanning the sky the eROSITA X-ray telescope aboard SRG orbital observatory produced the best ever X-ray maps of the sky and discovered more than three million X-ray sources, of which about 20% are stars with active coronas in the Milky Way, and most of the rest are galaxies with active nuclei, quasars and clusters of galaxies. eROSITA detected over 10^3 sources...
5 years after the launch from the Russian Baikonur Cosmodrome, all systems and instruments of the Spektr-RG (SRG) observatory are working perfectly. With eROSITA, the German contribution to this mission, half of all 8 sky surveys have been completed so far. Millions of X-ray sources, mostly of an extragalactic nature, have been discovered. This has confirmed what we had hoped for before the...
An overview of highlights and discoveries from Mikhail Pavlinsky ART-XC telescope on board the SRG observatory is presented. Since 2019 SRG/ART-XC has conducted several full all sky surveys as well as a deep survey of our Galaxy. As a result, we obtained the catalogue of hard X-ray sources detected at the all sky, which includes more than one and a half thousand objects, most of them are...
During the 2.5 years in 2019-2022 the eROSITA telescope onboard the SRG space observatory produced a deep all-sky survey in soft X-rays. The competitive analysis of this unique data requires: firstly, massive usage of publicly available sky surveys (photometric, spectroscopic, astrometric) in the broad spectral range from Radio to UV; secondly - intensive application of modern machine learning...
SRG/eROSITA and microwave observations of clusters of galaxies
The Einstein Probe mission is a dedicated satellite for time-domain astrophysics collaborated with ESA, MPE as well as CNES, which was launched on Jan. 9, 2024. There are two payloads onboard EP, the Wide-Field X-ray telescope (WXT) and the Follow-up X-ray telescope (FXT). WXT employ the Lobster-Eye Optics with FOV of about 3830 square degrees by 12 modules. FXT employ traditional Wolter-I...
Wide Field Survey Telescope (WFST) is the largest time-domain survey facility in the northern hemisphere. The telescope is a dedicated photometric surveying facility being built jointly by the University of Science and Technology of China (USTC) and the Purple Mountain Observatory(PMO). It is equipped with a 2.5-meter diameter primary mirror, an active optics system, and a mosaic CCD camera...
As China's first X-ray astronomy satellite, Insight-HXMT has been successfully operating in orbit for over seven years since its launch in 2017, producing substantial findings in the study of compact objects. As a next-generation space mission, CATCH will utilize the collaborative capabilities of a multi-satellite constellation, presenting significant scientific potential in exploring the...
The INTEGRAL hard X-ray surveys have proven to be of fundamental importance. In more than twenty years of operation, the INTEGRAL observatory has given us a sharper view of the hard X-ray sky, and provided the triggers for many follow-up campaigns from radio frequencies to gamma-rays. In addition to conducting a census of hard X-ray sources across the entire sky, INTEGRAL has carried out...
