Observability of HOFNARs at SRG/eROSITA
Neutron stars can appear as sources of different nature. In this paper we address the observability of a hypothetical class of neutron stars—HOt and Fast Non-Accreting Rotators, HOFNARs. These objects are heated due to the r-mode instability. With surface temperatures ∼10<sup>6</sup> K t...
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MDPI AG
2022-06-01
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| Series: | Universe |
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| Online Access: | https://www.mdpi.com/2218-1997/8/7/354 |
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| author | Alena D. Khokhriakova Andrey I. Chugunov Sergei B. Popov Mikhail E. Gusakov Elena M. Kantor |
| author_facet | Alena D. Khokhriakova Andrey I. Chugunov Sergei B. Popov Mikhail E. Gusakov Elena M. Kantor |
| author_sort | Alena D. Khokhriakova |
| collection | DOAJ |
| description | Neutron stars can appear as sources of different nature. In this paper we address the observability of a hypothetical class of neutron stars—HOt and Fast Non-Accreting Rotators, HOFNARs. These objects are heated due to the r-mode instability. With surface temperatures ∼10<sup>6</sup> K they are expected to be thermal soft X-ray emitters. We perform a population synthesis modeling of HOFNARs to predict the number of potentially detectable sources in the eROSITA all-sky survey. For surface temperatures ∼10<sup>6</sup> K we obtain ∼500 sources above the detection limit 0.01 cts s<sup>−1</sup> and ∼100 easier identifiable sources with >0.1 cts s<sup>−1</sup>. Temperatures ≳1.2 × 10<sup>6</sup> K start to be in contradiction with non-detection of HOFNARs by ROSAT. Only for <i>T</i> ≲ 5 × 10<sup>5</sup> K numbers predicted for eROSITA turn out to be so low that identification does not look possible. We conclude that eROSITA has good chances to discover HOFNARs, if they exist. Non-detection will put very stringent limits on the properties of this type of neutron stars. |
| first_indexed | 2024-03-09T10:10:27Z |
| format | Article |
| id | doaj.art-709b4ca9346e4308bbfb115bf07d4b7a |
| institution | Directory Open Access Journal |
| issn | 2218-1997 |
| language | English |
| last_indexed | 2024-03-09T10:10:27Z |
| publishDate | 2022-06-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Universe |
| spelling | doaj.art-709b4ca9346e4308bbfb115bf07d4b7a2023-12-01T22:45:49ZengMDPI AGUniverse2218-19972022-06-018735410.3390/universe8070354Observability of HOFNARs at SRG/eROSITAAlena D. Khokhriakova0Andrey I. Chugunov1Sergei B. Popov2Mikhail E. Gusakov3Elena M. Kantor4Department of Physics, Lomonosov Moscow State University, 119991 Moscow, RussiaIoffe Institute, 194021 St. Petersburg, RussiaDepartment of Physics, Lomonosov Moscow State University, 119991 Moscow, RussiaIoffe Institute, 194021 St. Petersburg, RussiaIoffe Institute, 194021 St. Petersburg, RussiaNeutron stars can appear as sources of different nature. In this paper we address the observability of a hypothetical class of neutron stars—HOt and Fast Non-Accreting Rotators, HOFNARs. These objects are heated due to the r-mode instability. With surface temperatures ∼10<sup>6</sup> K they are expected to be thermal soft X-ray emitters. We perform a population synthesis modeling of HOFNARs to predict the number of potentially detectable sources in the eROSITA all-sky survey. For surface temperatures ∼10<sup>6</sup> K we obtain ∼500 sources above the detection limit 0.01 cts s<sup>−1</sup> and ∼100 easier identifiable sources with >0.1 cts s<sup>−1</sup>. Temperatures ≳1.2 × 10<sup>6</sup> K start to be in contradiction with non-detection of HOFNARs by ROSAT. Only for <i>T</i> ≲ 5 × 10<sup>5</sup> K numbers predicted for eROSITA turn out to be so low that identification does not look possible. We conclude that eROSITA has good chances to discover HOFNARs, if they exist. Non-detection will put very stringent limits on the properties of this type of neutron stars.https://www.mdpi.com/2218-1997/8/7/354neutron starsmagnetic fieldmillisecond radio pulsarsX-ray binary systems |
| spellingShingle | Alena D. Khokhriakova Andrey I. Chugunov Sergei B. Popov Mikhail E. Gusakov Elena M. Kantor Observability of HOFNARs at SRG/eROSITA Universe neutron stars magnetic field millisecond radio pulsars X-ray binary systems |
| title | Observability of HOFNARs at SRG/eROSITA |
| title_full | Observability of HOFNARs at SRG/eROSITA |
| title_fullStr | Observability of HOFNARs at SRG/eROSITA |
| title_full_unstemmed | Observability of HOFNARs at SRG/eROSITA |
| title_short | Observability of HOFNARs at SRG/eROSITA |
| title_sort | observability of hofnars at srg erosita |
| topic | neutron stars magnetic field millisecond radio pulsars X-ray binary systems |
| url | https://www.mdpi.com/2218-1997/8/7/354 |
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