Rebrightening of 1 Crab from LS V+44 17 observed by Swift/BAT and NICER

Sabyasachi  Pal; Manoj Mandal; Keith C. Gendreau; Christian Malacaria; Wataru Buz Iwakiri; Zaven Arzoumanian; Gaurava K. Jaisawal; Andrea Sanna; Michael T. Wolff; Elizabeth C. Ferrara; Alexander  Salganik; Joel B. Coley; Katja Pottschmidt; James F. Steiner; Mason Ng; Paul S. Ray

Rebrightening of 1 Crab from LS V+44 17 observed by Swift/BAT and NICER

Sabyasachi Pal , Manoj Mandal^*, Keith C. Gendreau, Christian Malacaria, Wataru Buz Iwakiri , Zaven Arzoumanian, Gaurava K. Jaisawal, Andrea Sanna, Michael T. Wolff, Elizabeth C. Ferrara, Alexander Salganik, Joel B. Coley, Katja Pottschmidt, James F. Steiner, Mason Ng, Paul S. Ray

^*Corresponding author for this work

Research output: Other contribution › Net publication - Internet publication › Research

Abstract

We report rebrightening from the Be/X-ray binary pulsar LS V +44 17 (also known as RX J0440.9+4431) detected by NICER, Swift/BAT and MAXI/GSC. The pulsar was recently reported to be in an X-ray outburst (ATel #15835, #15848).

The Swift/BAT X-ray flux from the source was seen to increase from December 24 (MJD 59937) and reached 572±43 mCrab on MJD 59948 (ATel #15835, #15848) before starting to decrease. From MJD 59958, the X-ray flux of LS V +44 17 began to increase again in Swift/BAT (15−50 keV). During the rebrightening phase, the X-ray flux has so far reached a record high of 1.086±0.06 Crab as observed by Swift/BAT (15−50 keV) on MJD 59964. MAXI/GSC (2−20 keV) flux has also been increasing and reached nearly 134 mCrab on MJD 59961.5.

NICER observed the source regularly beginning on December 29 at 19:01:00 UTC (MJD 59942.79). The pulse period reported in the earlier ATel# 15848 was incorrect. A strong pulsation with period ∼208±0.01 s (after barycentric correction) is evident in NICER data from December 29 (MJD 59942.79). The spin period decreased at a rate of nearly 0.016 s/d between MJD 59942 and MJD 59960. The pulse profile also shows a double-peak feature. The fractional amplitude of the profile is found to be ∼43±3% (0.5−10 keV).

The recent NICER observation of the source during the rebrightened phase on MJD 59963.507 recorded a peak count rate of ∼1000 cnts/s (0.5−10 keV). The NICER spectrum at MJD 59963.507 can be fitted with an absorbed cutoff power-law model together with a blackbody component. The best-fit results provide a photon index of −0.16±0.21 and a column density of (0.43±0.03) × 10²² cm^-2 (chi-squared/d.o.f. = 775/749). The blackbody temperature is found to be 0.38±0.05 keV. A strong iron emission line is also detected at 6.38 keV with an equivalent width of nearly 0.07 keV. The absorbed source flux is ∼6.1 × 10^-9 ergs/cm²/s in 0.5−10 keV. All reported uncertainties have 90% confidence limits.

NICER is continuing to monitor the source. We encourage additional multi-wavelength observations.

Original language	English
Publication date	20 Jan 2023
Publication status	Published - 20 Jan 2023

Series	The Astronomer's telegram
Number	ATel #15868

Keywords

X-ray
Neutron Star
Star
Transient
Pulsar

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Pal , S., Mandal, M., Gendreau, K. C., Malacaria, C., Buz Iwakiri , W., Arzoumanian, Z., Jaisawal, G. K., Sanna, A., Wolff, M. T., Ferrara, E. C., Salganik, A., Coley, J. B., Pottschmidt, K., Steiner, J. F., Ng, M., & Ray, P. S. (2023, Jan 20). Rebrightening of 1 Crab from LS V+44 17 observed by Swift/BAT and NICER. The Astronomer's telegram No. ATel #15868 https://www.astronomerstelegram.org/?read=15868

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title = "Rebrightening of 1 Crab from LS V+44 17 observed by Swift/BAT and NICER",

abstract = "We report rebrightening from the Be/X-ray binary pulsar LS V +44 17 (also known as RX J0440.9+4431) detected by NICER, Swift/BAT and MAXI/GSC. The pulsar was recently reported to be in an X-ray outburst (ATel #15835, #15848). The Swift/BAT X-ray flux from the source was seen to increase from December 24 (MJD 59937) and reached 572±43 mCrab on MJD 59948 (ATel #15835, #15848) before starting to decrease. From MJD 59958, the X-ray flux of LS V +44 17 began to increase again in Swift/BAT (15−50 keV). During the rebrightening phase, the X-ray flux has so far reached a record high of 1.086±0.06 Crab as observed by Swift/BAT (15−50 keV) on MJD 59964. MAXI/GSC (2−20 keV) flux has also been increasing and reached nearly 134 mCrab on MJD 59961.5. NICER observed the source regularly beginning on December 29 at 19:01:00 UTC (MJD 59942.79). The pulse period reported in the earlier ATel# 15848 was incorrect. A strong pulsation with period ∼208±0.01 s (after barycentric correction) is evident in NICER data from December 29 (MJD 59942.79). The spin period decreased at a rate of nearly 0.016 s/d between MJD 59942 and MJD 59960. The pulse profile also shows a double-peak feature. The fractional amplitude of the profile is found to be ∼43±3% (0.5−10 keV). The recent NICER observation of the source during the rebrightened phase on MJD 59963.507 recorded a peak count rate of ∼1000 cnts/s (0.5−10 keV). The NICER spectrum at MJD 59963.507 can be fitted with an absorbed cutoff power-law model together with a blackbody component. The best-fit results provide a photon index of −0.16±0.21 and a column density of (0.43±0.03) × 1022 cm-2 (chi-squared/d.o.f. = 775/749). The blackbody temperature is found to be 0.38±0.05 keV. A strong iron emission line is also detected at 6.38 keV with an equivalent width of nearly 0.07 keV. The absorbed source flux is ∼6.1 × 10-9 ergs/cm2/s in 0.5−10 keV. All reported uncertainties have 90% confidence limits. NICER is continuing to monitor the source. We encourage additional multi-wavelength observations.",

keywords = "X-ray, Neutron Star, Star, Transient, Pulsar",

author = "Sabyasachi Pal and Manoj Mandal and Gendreau, {Keith C.} and Christian Malacaria and {Buz Iwakiri}, Wataru and Zaven Arzoumanian and Jaisawal, {Gaurava K.} and Andrea Sanna and Wolff, {Michael T.} and Ferrara, {Elizabeth C.} and Alexander Salganik and Coley, {Joel B.} and Katja Pottschmidt and Steiner, {James F.} and Mason Ng and Ray, {Paul S.}",

year = "2023",

month = jan,

day = "20",

language = "English",

series = "The Astronomer's telegram",

publisher = "R. Rutledge",

number = "ATel #15868",

type = "Other",

}

TY - ICOMM

T1 - Rebrightening of 1 Crab from LS V+44 17 observed by Swift/BAT and NICER

AU - Pal , Sabyasachi

AU - Mandal, Manoj

AU - Gendreau, Keith C.

AU - Malacaria, Christian

AU - Buz Iwakiri , Wataru

AU - Arzoumanian, Zaven

AU - Jaisawal, Gaurava K.

AU - Sanna, Andrea

AU - Wolff, Michael T.

AU - Ferrara, Elizabeth C.

AU - Salganik, Alexander

AU - Coley, Joel B.

AU - Pottschmidt, Katja

AU - Steiner, James F.

AU - Ng, Mason

AU - Ray, Paul S.

PY - 2023/1/20

Y1 - 2023/1/20

N2 - We report rebrightening from the Be/X-ray binary pulsar LS V +44 17 (also known as RX J0440.9+4431) detected by NICER, Swift/BAT and MAXI/GSC. The pulsar was recently reported to be in an X-ray outburst (ATel #15835, #15848). The Swift/BAT X-ray flux from the source was seen to increase from December 24 (MJD 59937) and reached 572±43 mCrab on MJD 59948 (ATel #15835, #15848) before starting to decrease. From MJD 59958, the X-ray flux of LS V +44 17 began to increase again in Swift/BAT (15−50 keV). During the rebrightening phase, the X-ray flux has so far reached a record high of 1.086±0.06 Crab as observed by Swift/BAT (15−50 keV) on MJD 59964. MAXI/GSC (2−20 keV) flux has also been increasing and reached nearly 134 mCrab on MJD 59961.5. NICER observed the source regularly beginning on December 29 at 19:01:00 UTC (MJD 59942.79). The pulse period reported in the earlier ATel# 15848 was incorrect. A strong pulsation with period ∼208±0.01 s (after barycentric correction) is evident in NICER data from December 29 (MJD 59942.79). The spin period decreased at a rate of nearly 0.016 s/d between MJD 59942 and MJD 59960. The pulse profile also shows a double-peak feature. The fractional amplitude of the profile is found to be ∼43±3% (0.5−10 keV). The recent NICER observation of the source during the rebrightened phase on MJD 59963.507 recorded a peak count rate of ∼1000 cnts/s (0.5−10 keV). The NICER spectrum at MJD 59963.507 can be fitted with an absorbed cutoff power-law model together with a blackbody component. The best-fit results provide a photon index of −0.16±0.21 and a column density of (0.43±0.03) × 1022 cm-2 (chi-squared/d.o.f. = 775/749). The blackbody temperature is found to be 0.38±0.05 keV. A strong iron emission line is also detected at 6.38 keV with an equivalent width of nearly 0.07 keV. The absorbed source flux is ∼6.1 × 10-9 ergs/cm2/s in 0.5−10 keV. All reported uncertainties have 90% confidence limits. NICER is continuing to monitor the source. We encourage additional multi-wavelength observations.

AB - We report rebrightening from the Be/X-ray binary pulsar LS V +44 17 (also known as RX J0440.9+4431) detected by NICER, Swift/BAT and MAXI/GSC. The pulsar was recently reported to be in an X-ray outburst (ATel #15835, #15848). The Swift/BAT X-ray flux from the source was seen to increase from December 24 (MJD 59937) and reached 572±43 mCrab on MJD 59948 (ATel #15835, #15848) before starting to decrease. From MJD 59958, the X-ray flux of LS V +44 17 began to increase again in Swift/BAT (15−50 keV). During the rebrightening phase, the X-ray flux has so far reached a record high of 1.086±0.06 Crab as observed by Swift/BAT (15−50 keV) on MJD 59964. MAXI/GSC (2−20 keV) flux has also been increasing and reached nearly 134 mCrab on MJD 59961.5. NICER observed the source regularly beginning on December 29 at 19:01:00 UTC (MJD 59942.79). The pulse period reported in the earlier ATel# 15848 was incorrect. A strong pulsation with period ∼208±0.01 s (after barycentric correction) is evident in NICER data from December 29 (MJD 59942.79). The spin period decreased at a rate of nearly 0.016 s/d between MJD 59942 and MJD 59960. The pulse profile also shows a double-peak feature. The fractional amplitude of the profile is found to be ∼43±3% (0.5−10 keV). The recent NICER observation of the source during the rebrightened phase on MJD 59963.507 recorded a peak count rate of ∼1000 cnts/s (0.5−10 keV). The NICER spectrum at MJD 59963.507 can be fitted with an absorbed cutoff power-law model together with a blackbody component. The best-fit results provide a photon index of −0.16±0.21 and a column density of (0.43±0.03) × 1022 cm-2 (chi-squared/d.o.f. = 775/749). The blackbody temperature is found to be 0.38±0.05 keV. A strong iron emission line is also detected at 6.38 keV with an equivalent width of nearly 0.07 keV. The absorbed source flux is ∼6.1 × 10-9 ergs/cm2/s in 0.5−10 keV. All reported uncertainties have 90% confidence limits. NICER is continuing to monitor the source. We encourage additional multi-wavelength observations.

KW - X-ray

KW - Neutron Star

KW - Star

KW - Transient

KW - Pulsar

M3 - Net publication - Internet publication

T3 - The Astronomer's telegram

ER -

Rebrightening of 1 Crab from LS V+44 17 observed by Swift/BAT and NICER

Abstract

Keywords

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