2020
Neutron Star Radius-to-mass Ratio from Partial Accretion Disk Occultation as Measured through Fe K alpha Line Profiles
LA PLACA, Riccardo; Luigi STELLA; Alessandro PAPITTO; Pavel BAKALA; Tiziana DI SALVO et. al.Basic information
Original name
Neutron Star Radius-to-mass Ratio from Partial Accretion Disk Occultation as Measured through Fe K alpha Line Profiles
Authors
LA PLACA, Riccardo (380 Italy, belonging to the institution); Luigi STELLA (380 Italy); Alessandro PAPITTO; Pavel BAKALA (203 Czech Republic, belonging to the institution); Tiziana DI SALVO; Maurizio FALANGA; Vittorio DE FALCO (380 Italy, belonging to the institution) and Alessandra DE ROSA
Edition
Astrophysical Journal, 2020, 0004-637X
Other information
Language
English
Type of outcome
Article in a journal
Field of Study
10308 Astronomy
Country of publisher
United Kingdom of Great Britain and Northern Ireland
Confidentiality degree
is not subject to a state or trade secret
References:
Impact factor
Impact factor: 5.877
RIV identification code
RIV/47813059:19630/20:A0000082
Organization unit
Institute of physics in Opava
UT WoS
000529874600001
EID Scopus
2-s2.0-85085148364
Keywords in English
Neutron stars; Low-mass X-ray binary stars; Stellar accretion disks; General relativity; X-ray sources
Tags
International impact, Reviewed
Changed: 31/3/2022 10:13, Mgr. Pavlína Jalůvková
Abstract
In the original language
We present a new method to measure the radius-to-mass ratio (R/M) of weakly magnetic, disk-accreting neutron stars by exploiting the occultation of parts of the inner disk by the star itself. This occultation imprints characteristic features on the X-ray line profile that are unique and are expected to be present in low-mass X-ray binary systems seen under inclinations higher than 65 degrees. We analyze a Nuclear Spectroscopic Telescope Array observation of a good candidate system, 4U 1636-53, and find that X-ray spectra from current instrumentation are unlikely to single out the occultation features owing to insufficient signal-to-noise. Based on an extensive set of simulations we show that large-area X-ray detectors of the future generation could measure R/M to 2 3% precision over a range of inclinations. Such is the precision in radius determination required to derive tight constraints on the equation of state of ultradense matter and it represents the goal that other methods also aim to achieve in the future.