Blank Field X-Ray Sources
| dc.creator | Cagnoni, Ilaria | |
| dc.creator | Celotti, Annalisa | |
| dc.creator | Elvis, Martin | |
| dc.creator | Kim, Dong-Woo | |
| dc.creator | Nicastro, Fabrizio | |
| dc.date | 2000-06-19 | |
| dc.date.accessioned | 2026-07-07T01:54:02Z | |
| dc.date.available | 2026-07-07T01:54:02Z | |
| dc.description | The X-ray sky is not as well known as is sometimes thought. We report on our search of minority populations (Kim & Elvis 1999). One of the most intriguing is that of `blank field sources', i.e. bright ROSAT sources (F(X)>1e-13 erg/cm2/s) with no optical counterpart on the Palomar Sky Survey (to O=21.5) within their 39"(99%) radius error circle. The nature of Blank Field sources is unknown: no known extragalactic population has such extreme X-ray to optical ratios (f(X)/f(V) >60). Moreover blank field source tend to have much flatter PSPC spectra compared to radio-quiet AGN. Both properties suggest obscuration. `Blank field sources' could be: Quasar-2s, low-mass AGNs, isolated neutron stars, high redshift clusters of galaxies, failed clusters, AGNs with no big blue bump. Identification with any of these populations would be an interesting discovery. | |
| dc.description | 2 pages, to appear in the proceedings of the Fourth Italian Conference on AGNs (MemSAIt) | |
| dc.identifier | https://arxiv.org/abs/astro-ph/0006257 | |
| dc.identifier | http://arxiv.org/abs/astro-ph/0006257 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/1188 | |
| dc.subject | Astrophysics | |
| dc.title | Blank Field X-Ray Sources | |
| dc.type | text |