INTEGRAL/JEM-X and NICER follow-up observations of IGR J11435-6109 and 1E 1145.1-6141

G. K. Jaisawal; J. Chenevez; M.  Ng; P. S. Ray; K. C. Gendreau; Z. Arzoumanian

INTEGRAL/JEM-X and NICER follow-up observations of IGR J11435-6109 and 1E 1145.1-6141

G. K. Jaisawal^*, J. Chenevez, M. Ng, P. S. Ray, K. C. Gendreau, Z. Arzoumanian

^*Corresponding author for this work

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

Abstract

The recent INTEGRAL/JEM-X observation of the Galactic Plane (PI: A. Bazzano) between 2022-11-05T22:18 and 2022-11-06T17:58 UTC revisited the field of high mass X-ray binary pulsars, IGR J11435-6109 and 1E 1145.1-6141, for an exposure time of 66 ks under INTEGRAL revolution 2568. JEM-X detected both targets in 3-10 and 10-25 keV bands, respectively, at the following intensity levels:

IGR J11435-6109: 6.4+/-1 mCrab and 7+/- 3 mCrab
1E 1145.1-6141: 6.6+/-1 mCrab and 6.4+/- 3 mCrab

These observed X-ray intensities indicate, even if marginally significant, a decline for both sources compared to our previous measurements obtained a week ago also with JEM-X (ATEL #15741). Such a decline in intensities would signify that both sources are in short-lived outbursting states or were observed by INTEGRAL/JEM-X mainly in the decline phases of the outbursts.

We further followed these two sources with NICER. IGR J11435-6109 was observed by NICER on 3-4 November 2022 with an effective exposure of 180 s. The corresponding 1-10 keV spectrum can be fitted with an absorbed power law with an index of 0.92+/-0.15 and a column density of 1.9+/-0.3 × 10²² cm^-2 (chi-squared/d.o.f. = 71/62). The column density is consistent with the HI4PI survey which is 1.15× 10²² cm^-2 along the source direction. We found a 1-10 keV flux of 1.2 × 10^-10 erg/s/cm². Considering a source distance of 8 kpc (Bouchet et al. 2022, MNRAS, 517, 3034), the unabsorbed X-ray luminosity is estimated to be 1.1 × 10³⁶ erg/s.

1E 1145.1-6141 was also observed by NICER on 5th November 2022 for an effective exposure of 194 s. We fit the 1-8 keV source spectrum using an absorbed power-law model, leading to a photon index of 2.3+/-0.7 and a column density of (7.8+/-3) × 10²² cm^-2 (chi-squared/d.o.f. = 95/84). The 1-10 keV X-ray flux is measured as 3.8 × 10^-11 erg/s/cm². Correspondingly, the unabsorbed X-ray luminosity is calculated to be 9 × 10³⁵ erg/s assuming a source distance of 8.5 kpc (Densham & Charles 1982, MNRAS, 201, 171).

NICER is a 0.2-12 keV X-ray telescope operating on the International Space Station. The NICER mission and portions of the NICER science team activities are funded by NASA.

Original language	English
Publication date	9 Nov 2022
Publication status	Published - 9 Nov 2022

Series	The Astronomer's telegram
Number	ATel #15750

Keywords

X-ray
Transient
Pulsar

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@misc{3044f1b84e53472092c863d5b36ce0cc,

title = "INTEGRAL/JEM-X and NICER follow-up observations of IGR J11435-6109 and 1E 1145.1-6141",

abstract = "The recent INTEGRAL/JEM-X observation of the Galactic Plane (PI: A. Bazzano) between 2022-11-05T22:18 and 2022-11-06T17:58 UTC revisited the field of high mass X-ray binary pulsars, IGR J11435-6109 and 1E 1145.1-6141, for an exposure time of 66 ks under INTEGRAL revolution 2568. JEM-X detected both targets in 3-10 and 10-25 keV bands, respectively, at the following intensity levels: IGR J11435-6109: 6.4+/-1 mCrab and 7+/- 3 mCrab 1E 1145.1-6141: 6.6+/-1 mCrab and 6.4+/- 3 mCrab These observed X-ray intensities indicate, even if marginally significant, a decline for both sources compared to our previous measurements obtained a week ago also with JEM-X (ATEL #15741). Such a decline in intensities would signify that both sources are in short-lived outbursting states or were observed by INTEGRAL/JEM-X mainly in the decline phases of the outbursts. We further followed these two sources with NICER. IGR J11435-6109 was observed by NICER on 3-4 November 2022 with an effective exposure of 180 s. The corresponding 1-10 keV spectrum can be fitted with an absorbed power law with an index of 0.92+/-0.15 and a column density of 1.9+/-0.3 × 1022 cm-2 (chi-squared/d.o.f. = 71/62). The column density is consistent with the HI4PI survey which is 1.15× 1022 cm-2 along the source direction. We found a 1-10 keV flux of 1.2 × 10-10 erg/s/cm2. Considering a source distance of 8 kpc (Bouchet et al. 2022, MNRAS, 517, 3034), the unabsorbed X-ray luminosity is estimated to be 1.1 × 1036 erg/s. 1E 1145.1-6141 was also observed by NICER on 5th November 2022 for an effective exposure of 194 s. We fit the 1-8 keV source spectrum using an absorbed power-law model, leading to a photon index of 2.3+/-0.7 and a column density of (7.8+/-3) × 1022 cm-2 (chi-squared/d.o.f. = 95/84). The 1-10 keV X-ray flux is measured as 3.8 × 10-11 erg/s/cm2. Correspondingly, the unabsorbed X-ray luminosity is calculated to be 9 × 1035 erg/s assuming a source distance of 8.5 kpc (Densham & Charles 1982, MNRAS, 201, 171). NICER is a 0.2-12 keV X-ray telescope operating on the International Space Station. The NICER mission and portions of the NICER science team activities are funded by NASA. ",

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

author = "Jaisawal, {G. K.} and J. Chenevez and M. Ng and Ray, {P. S.} and Gendreau, {K. C.} and Z. Arzoumanian",

year = "2022",

month = nov,

day = "9",

language = "English",

series = "The Astronomer's telegram",

publisher = "R. Rutledge",

number = "ATel #15750",

type = "Other",

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TY - ICOMM

T1 - INTEGRAL/JEM-X and NICER follow-up observations of IGR J11435-6109 and 1E 1145.1-6141

AU - Jaisawal, G. K.

AU - Chenevez, J.

AU - Ng, M.

AU - Ray, P. S.

AU - Gendreau, K. C.

AU - Arzoumanian, Z.

PY - 2022/11/9

Y1 - 2022/11/9

N2 - The recent INTEGRAL/JEM-X observation of the Galactic Plane (PI: A. Bazzano) between 2022-11-05T22:18 and 2022-11-06T17:58 UTC revisited the field of high mass X-ray binary pulsars, IGR J11435-6109 and 1E 1145.1-6141, for an exposure time of 66 ks under INTEGRAL revolution 2568. JEM-X detected both targets in 3-10 and 10-25 keV bands, respectively, at the following intensity levels: IGR J11435-6109: 6.4+/-1 mCrab and 7+/- 3 mCrab 1E 1145.1-6141: 6.6+/-1 mCrab and 6.4+/- 3 mCrab These observed X-ray intensities indicate, even if marginally significant, a decline for both sources compared to our previous measurements obtained a week ago also with JEM-X (ATEL #15741). Such a decline in intensities would signify that both sources are in short-lived outbursting states or were observed by INTEGRAL/JEM-X mainly in the decline phases of the outbursts. We further followed these two sources with NICER. IGR J11435-6109 was observed by NICER on 3-4 November 2022 with an effective exposure of 180 s. The corresponding 1-10 keV spectrum can be fitted with an absorbed power law with an index of 0.92+/-0.15 and a column density of 1.9+/-0.3 × 1022 cm-2 (chi-squared/d.o.f. = 71/62). The column density is consistent with the HI4PI survey which is 1.15× 1022 cm-2 along the source direction. We found a 1-10 keV flux of 1.2 × 10-10 erg/s/cm2. Considering a source distance of 8 kpc (Bouchet et al. 2022, MNRAS, 517, 3034), the unabsorbed X-ray luminosity is estimated to be 1.1 × 1036 erg/s. 1E 1145.1-6141 was also observed by NICER on 5th November 2022 for an effective exposure of 194 s. We fit the 1-8 keV source spectrum using an absorbed power-law model, leading to a photon index of 2.3+/-0.7 and a column density of (7.8+/-3) × 1022 cm-2 (chi-squared/d.o.f. = 95/84). The 1-10 keV X-ray flux is measured as 3.8 × 10-11 erg/s/cm2. Correspondingly, the unabsorbed X-ray luminosity is calculated to be 9 × 1035 erg/s assuming a source distance of 8.5 kpc (Densham & Charles 1982, MNRAS, 201, 171). NICER is a 0.2-12 keV X-ray telescope operating on the International Space Station. The NICER mission and portions of the NICER science team activities are funded by NASA.

AB - The recent INTEGRAL/JEM-X observation of the Galactic Plane (PI: A. Bazzano) between 2022-11-05T22:18 and 2022-11-06T17:58 UTC revisited the field of high mass X-ray binary pulsars, IGR J11435-6109 and 1E 1145.1-6141, for an exposure time of 66 ks under INTEGRAL revolution 2568. JEM-X detected both targets in 3-10 and 10-25 keV bands, respectively, at the following intensity levels: IGR J11435-6109: 6.4+/-1 mCrab and 7+/- 3 mCrab 1E 1145.1-6141: 6.6+/-1 mCrab and 6.4+/- 3 mCrab These observed X-ray intensities indicate, even if marginally significant, a decline for both sources compared to our previous measurements obtained a week ago also with JEM-X (ATEL #15741). Such a decline in intensities would signify that both sources are in short-lived outbursting states or were observed by INTEGRAL/JEM-X mainly in the decline phases of the outbursts. We further followed these two sources with NICER. IGR J11435-6109 was observed by NICER on 3-4 November 2022 with an effective exposure of 180 s. The corresponding 1-10 keV spectrum can be fitted with an absorbed power law with an index of 0.92+/-0.15 and a column density of 1.9+/-0.3 × 1022 cm-2 (chi-squared/d.o.f. = 71/62). The column density is consistent with the HI4PI survey which is 1.15× 1022 cm-2 along the source direction. We found a 1-10 keV flux of 1.2 × 10-10 erg/s/cm2. Considering a source distance of 8 kpc (Bouchet et al. 2022, MNRAS, 517, 3034), the unabsorbed X-ray luminosity is estimated to be 1.1 × 1036 erg/s. 1E 1145.1-6141 was also observed by NICER on 5th November 2022 for an effective exposure of 194 s. We fit the 1-8 keV source spectrum using an absorbed power-law model, leading to a photon index of 2.3+/-0.7 and a column density of (7.8+/-3) × 1022 cm-2 (chi-squared/d.o.f. = 95/84). The 1-10 keV X-ray flux is measured as 3.8 × 10-11 erg/s/cm2. Correspondingly, the unabsorbed X-ray luminosity is calculated to be 9 × 1035 erg/s assuming a source distance of 8.5 kpc (Densham & Charles 1982, MNRAS, 201, 171). NICER is a 0.2-12 keV X-ray telescope operating on the International Space Station. The NICER mission and portions of the NICER science team activities are funded by NASA.

KW - X-ray

KW - Transient

KW - Pulsar

M3 - Net publication - Internet publication

T3 - The Astronomer's telegram

ER -

INTEGRAL/JEM-X and NICER follow-up observations of IGR J11435-6109 and 1E 1145.1-6141

Abstract

Keywords

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