TY - JOUR
T1 - A deep campaign to characterize the synchronous radio/X-ray mode switching of PSR B0943+10
AU - Mereghetti, S.
AU - Kuiper, L
AU - {Tiengo}, A
AU - Hessels, J
AU - Hermsen, W
AU - Stovall, K
AU - Possenti, A
AU - Rankin, J
AU - Esposito, P.
AU - Turolla, R.
AU - Mitra, D.
AU - Wright, G
AU - Stappers, Benjamin
AU - Horneffer, A
AU - Oslowski, S.
AU - Serylak, M
AU - Griebmeier, J.-M.
PY - 2016/10/24
Y1 - 2016/10/24
N2 - Observations of PSR B0943+10 with XMM-Newton and the LOFAR, LWA, and Arecibo radio telescopes in 2014 November confirm the synchronous X-ray/radio switching between a radio-bright (B) mode and a radio-quiet (Q) mode, in which the X-ray flux is a factor ~2.4 higher than in the B-mode. We discovered X-ray pulsations during the B-mode (0.5–2 keV pulsed fraction of (38 ± 5)%) and confirm their presence in the Q-mode, where the pulsed fraction increases with energy from ~20% to ~65% at 2 keV. We found marginal evidence for an increase in the X-ray pulsed fraction during the B-mode on a timescale of hours. The X-ray spectrum during the Q-mode requires a fit with either a power law plus blackbody or the sum of two blackbodies, while in the B-mode it is well fit by a single blackbody (a single power law is rejected). In the Q-mode, the pulsed emission has a blackbody spectrum with temperature ~3.4 x 106K and the unpulsed emission is a power law with photon index ~2.5, while during the B-mode both the pulsed and unpulsed emission can be fit by either a blackbody or a power law with similar values of temperature and index. A Chandra image does not show diffuse X-ray emission. These results support a scenario in which unpulsed non-thermal emission, likely magnetospheric, and pulsed thermal emission from a small polar cap (~1500 m2) with a non-dipolar field (~1014 G) are present during both modes and vary in a correlated way. This is broadly consistent with the partially screened gap model and does not necessarily imply global magnetospheric rearrangements to explain the mode switching.
AB - Observations of PSR B0943+10 with XMM-Newton and the LOFAR, LWA, and Arecibo radio telescopes in 2014 November confirm the synchronous X-ray/radio switching between a radio-bright (B) mode and a radio-quiet (Q) mode, in which the X-ray flux is a factor ~2.4 higher than in the B-mode. We discovered X-ray pulsations during the B-mode (0.5–2 keV pulsed fraction of (38 ± 5)%) and confirm their presence in the Q-mode, where the pulsed fraction increases with energy from ~20% to ~65% at 2 keV. We found marginal evidence for an increase in the X-ray pulsed fraction during the B-mode on a timescale of hours. The X-ray spectrum during the Q-mode requires a fit with either a power law plus blackbody or the sum of two blackbodies, while in the B-mode it is well fit by a single blackbody (a single power law is rejected). In the Q-mode, the pulsed emission has a blackbody spectrum with temperature ~3.4 x 106K and the unpulsed emission is a power law with photon index ~2.5, while during the B-mode both the pulsed and unpulsed emission can be fit by either a blackbody or a power law with similar values of temperature and index. A Chandra image does not show diffuse X-ray emission. These results support a scenario in which unpulsed non-thermal emission, likely magnetospheric, and pulsed thermal emission from a small polar cap (~1500 m2) with a non-dipolar field (~1014 G) are present during both modes and vary in a correlated way. This is broadly consistent with the partially screened gap model and does not necessarily imply global magnetospheric rearrangements to explain the mode switching.
U2 - 10.3847/0004-637X/831/1/21
DO - 10.3847/0004-637X/831/1/21
M3 - Article
SN - 0004-637X
VL - 831
JO - The Astrophysical Journal
JF - The Astrophysical Journal
IS - 1
ER -