Periodicity from X-ray sources within the inner Galactic disk

Fuente: arXiv
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Main Authors: Mondal, Samaresh, Ponti, Gabriele, Bao, Tong, Haberl, Frank, Campana, Sergio, Hailey, Charles J., Mandel, Shifra, Mereghetti, Sandro, Mori, Kaya, Morris, Mark R., Rea, Nanda, Sidoli, Lara
Format: Preprint
Published: 2024
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author Mondal, Samaresh
Ponti, Gabriele
Bao, Tong
Haberl, Frank
Campana, Sergio
Hailey, Charles J.
Mandel, Shifra
Mereghetti, Sandro
Mori, Kaya
Morris, Mark R.
Rea, Nanda
Sidoli, Lara
author_facet Mondal, Samaresh
Ponti, Gabriele
Bao, Tong
Haberl, Frank
Campana, Sergio
Hailey, Charles J.
Mandel, Shifra
Mereghetti, Sandro
Mori, Kaya
Morris, Mark R.
Rea, Nanda
Sidoli, Lara
contents For many years, it has been claimed that the Galactic ridge X-ray emission at the Galactic Center (GC) is truly diffuse in nature. However, with the advancement of modern X-ray satellites, it has been found that most of the diffuse emission is actually comprised of thousands of previously unresolved X-ray point sources. Further, many studies suggest that a vast majority of these X-ray point sources are magnetic cataclysmic variables (mCVs) and active binaries. One unambiguous way to identify these mCVs and other sources is by detecting their X-ray periodicity. Therefore, we systematically searched for periodic X-ray sources in the inner Galactic disk, including the GC region. We have used data from our ongoing XMM-Newton Heritage survey of the inner Galactic disk ($350^{\circ}\lesssim l\lesssim+7^{\circ}$ and $-1^{\circ}\lesssim b\lesssim +1^{\circ}$) plus the XMM-Newton archival observations of the GC. We computed the Lomb-Scargle periodogram of the light curves for the periodicity search. We fitted the energy spectra of the sources using a simple power-law model plus three Gaussians at 6.4, 6.7, and 6.9 keV for the iron $K$ emission complex. We detected periodicity in 26 sources. For 14 of them, this is the first discovery of periodicity. For the other 12 sources, we found periods similar to those already known, indicating no significant period evolution. We also searched for the Gaia counterparts of the periodic sources to estimate their distances using the Gaia parallax. We found a likely Gaia counterpart for seven sources. We have classified the sources into four categories based on the periodicity, hardness ratio, and the equivalent width of Fe $K$ line emission. Of the 14 sources where we detect the periodicity for the first time, four are likely to be intermediate polars, five are likely to be polars, two are neutron star X-ray binaries, and three are of unknown nature.
format Preprint
id arxiv_https___arxiv_org_abs_2403_14480
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Periodicity from X-ray sources within the inner Galactic disk
Mondal, Samaresh
Ponti, Gabriele
Bao, Tong
Haberl, Frank
Campana, Sergio
Hailey, Charles J.
Mandel, Shifra
Mereghetti, Sandro
Mori, Kaya
Morris, Mark R.
Rea, Nanda
Sidoli, Lara
High Energy Astrophysical Phenomena
For many years, it has been claimed that the Galactic ridge X-ray emission at the Galactic Center (GC) is truly diffuse in nature. However, with the advancement of modern X-ray satellites, it has been found that most of the diffuse emission is actually comprised of thousands of previously unresolved X-ray point sources. Further, many studies suggest that a vast majority of these X-ray point sources are magnetic cataclysmic variables (mCVs) and active binaries. One unambiguous way to identify these mCVs and other sources is by detecting their X-ray periodicity. Therefore, we systematically searched for periodic X-ray sources in the inner Galactic disk, including the GC region. We have used data from our ongoing XMM-Newton Heritage survey of the inner Galactic disk ($350^{\circ}\lesssim l\lesssim+7^{\circ}$ and $-1^{\circ}\lesssim b\lesssim +1^{\circ}$) plus the XMM-Newton archival observations of the GC. We computed the Lomb-Scargle periodogram of the light curves for the periodicity search. We fitted the energy spectra of the sources using a simple power-law model plus three Gaussians at 6.4, 6.7, and 6.9 keV for the iron $K$ emission complex. We detected periodicity in 26 sources. For 14 of them, this is the first discovery of periodicity. For the other 12 sources, we found periods similar to those already known, indicating no significant period evolution. We also searched for the Gaia counterparts of the periodic sources to estimate their distances using the Gaia parallax. We found a likely Gaia counterpart for seven sources. We have classified the sources into four categories based on the periodicity, hardness ratio, and the equivalent width of Fe $K$ line emission. Of the 14 sources where we detect the periodicity for the first time, four are likely to be intermediate polars, five are likely to be polars, two are neutron star X-ray binaries, and three are of unknown nature.
title Periodicity from X-ray sources within the inner Galactic disk
topic High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2403.14480