Manoneeta Chakraborty | Indian Institute of Technology Indore (original) (raw)

Papers by Manoneeta Chakraborty

ABSTRACT We report Rossi X-ray Timing Explorer data analysis of the Terzan 5 source IGR J17480-24... more ABSTRACT We report Rossi X-ray Timing Explorer data analysis of the Terzan 5 source IGR J17480-2446, which is currently in outburst (ATels #2919, #2920, #2922, #2924, #2929, #2932, #2933, #2935, #2937, #2939, #2946, #2952, #2958, #2974, #3000). Galloway and in 't Zand (ATel #3000) reported that after the 2010 October 13 thermonuclear burst, no other burst up to 2010 October 26 showed significant (>2 sigma confidence) cooling during burst decay.

Plasma accreted onto the surface of a neutron star can ignite due to unstable thermonuclear burni... more Plasma accreted onto the surface of a neutron star can ignite due to unstable thermonuclear burning and produce a bright flash of X-ray emission called a Type-I X-ray burst. Such events are very common; thousands have been observed to date from over a hundred accreting neutron stars. The intense, often Eddington-limited, radiation generated in these thermonuclear explosions can have a discernible effect on the surrounding accretion flow that consists of an accretion disk and a hot electron corona. Type-I X-ray bursts can thereB N. Degenaar N.D.Degenaar@uva.nl 1 Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 OHA, UK 2 Anton Pannekoek Institute, University of Amsterdam, Science Park 904, 1098, Amsterdam, The Netherlands 3 School of Physics, Georgia Institute of Technology, Center for Relativistic Astrophysics, Atlanta, GA 30332, USA 4 Istituto Nazionale di Astrofisica, Osservatorio Astronomico di Brera, Via E. Bianchi 46, 23807 Merate, Italy 5 Faculty o...

arXiv: High Energy Astrophysical Phenomena, 2020

The giant flares of soft gamma-ray repeaters (SGRs) have long been proposed to contribute to at l... more The giant flares of soft gamma-ray repeaters (SGRs) have long been proposed to contribute to at least a subsample of the observed short gamma-ray bursts (GRBs). In this paper, we perform a comprehensive analysis of the high-energy data of the recent bright short GRB 200415A, which was located close to the Sculptor galaxy. Our results suggest that a magnetar giant flare provides the most natural explanation for most observational properties of GRB 200415A, including its location, temporal and spectral features, energy, statistical correlations, and high-energy emissions. On the other hand, the compact star merger GRB model is found to have difficulty reproducing such an event in a nearby distance. Future detections and follow-up observations of similar events are essential to firmly establish the connection between SGR giant flares and a subsample of nearby short GRBs.

The Astrophysical Journal, 2021

We report the temporal and spectral analysis of three thermonuclear X-ray bursts from 4U 1608−52,... more We report the temporal and spectral analysis of three thermonuclear X-ray bursts from 4U 1608−52, observed by the Neutron Star Interior Composition Explorer (NICER) during and just after the outburst observed from the source in 2020. In two of the X-ray bursts, we detect secondary peaks 30 and 18 s after the initial peaks. The secondary peaks show a fast rise exponential decay-like shape resembling a thermonuclear X-ray burst. Time-resolved X-ray spectral analysis reveals that the peak flux, blackbody temperature, and apparent emitting radius values of the initial peaks are in agreement with X-ray bursts previously observed from 4U 1608−52, while the same values for the secondary peaks tend toward the lower end of the distribution of bursts observed from this source. The third X-ray burst, which happened during much lower accretion rates, did not show any evidence for a deviation from an exponential decay and was significantly brighter than the previous bursts. We present the proper...

We report the results of a long-term spectral and timing study of the first transient magnetar, X... more We report the results of a long-term spectral and timing study of the first transient magnetar, XTE J1810−197 which was discovered in 2003, when its X-ray luminosity increased ≈100 fold. We fit X-ray spectra of all archival X-ray observations using a two-component blackbody model, where the cool component is most likely originating from the whole surface of the neutron star and the hot component is from a much smaller hot spot. We investigate the long-term evolution of the surface emission characteristics via tracing its surface temperature, apparent emitting area and pulsed fraction. We evaluate the pulsed fraction in two energy intervals (< 1.5 keV and >1.5 keV) and show that the XTE J1810−197 exhibits slightly higher pulsed emission at energies above 1.5 keV. We explore the characteristics of an absorption line detected around 1.1 keV. We find that the absorption feature is highly variable and its profile is asymmetric. To accurately represent this feature, we introduced an...

Giant flares (GFs) are unusual bursts from soft gamma-ray repeaters (SGRs) that release an enormo... more Giant flares (GFs) are unusual bursts from soft gamma-ray repeaters (SGRs) that release an enormous amount of energy in a fraction of a second. The afterglow emission of these SGR-GFs or GF candidates is a highly beneficial means of discerning their composition, relativistic speed, and emission mechanisms. GRB 200415A is a recent GF candidate observed in a direction coincident with the nearby Sculptor galaxy at 3.5 Mpc. In this work, we searched for transient gamma-ray emission in past observations by Fermi-LAT in the direction of GRB 200415A. These observations confirm that GRB 200415A is observed as a transient GeV source only once. A pure pair-plasma fireball cannot provide the required energy for the interpretation of GeV afterglow emission and a baryonic poor outflow is additionally needed to explain the afterglow emission. A baryonic rich outflow is also viable, as it can explain the variability and observed quasi-thermal spectrum of the prompt emission if dissipation is happe...

Accreted matter falling on the surface of the neutron star in a Low Mass X-ray Binary (LMXB) syst... more Accreted matter falling on the surface of the neutron star in a Low Mass X-ray Binary (LMXB) system gives rise to intense X-r ay bursts originating from unstable thermonuclear conflagration and these bursts can be used as a tool to constrain the equation of state. A series o f such Xray bursts along with millihertz (mHz) quasi-periodic osci llat ons (QPOs) at the highest source luminosities were observed during the 2010 outburst of the transient LMXB pulsar IGR J17480–2446. The quite dive rse burst properties compared to typical type-I bursts suggested the m o be the typeII bursts originating from accretion disc instability. We s how that the bursts are indeed of thermonuclear origin and thus confirm the quasi -st ble burning model for mHz QPOs. Various properties of the bursts such as, peak flux, fluence, periodicity and duration, were highly depende nt on the source spectral states and their variation over a large accretion r ate range revealed the evolution of the burning process...

Publications of the Astronomical Society of Australia, 2021

We present the results of our extensive binary orbital motion corrected pulsation search for 13 l... more We present the results of our extensive binary orbital motion corrected pulsation search for 13 low-mass X-ray binaries. These selected sources exhibit burst oscillations in X-rays with frequencies ranging from 45 to 1 122 Hz and have a binary orbital period varying from 2.1 to 18.9 h. We first determined episodes that contain weak pulsations around the burst oscillation frequency by searching all archival Rossi X-ray Timing Explorer data of these sources. Then, we applied Doppler corrections to these pulsation episodes to discard the smearing effect of the binary orbital motion and searched for recovered pulsations at the second stage. Here we report 75 pulsation episodes that contain weak but coherent pulsations around the burst oscillation frequency. Furthermore, we report eight new episodes that show relatively strong pulsations in the binary orbital motion corrected data.

Research in Astronomy and Astrophysics

The Astrophysical Journal, Dec 14, 2017

We have investigated temporal and spectral properties of a large sample of thermonuclear bursts w... more We have investigated temporal and spectral properties of a large sample of thermonuclear bursts with oscillations from eight different sources with spin frequencies varying from 270 to 620 Hz. For our sample we chose those bursts, for which the oscillation is sufficiently strong and of relatively long duration. The emission from the hot-spot that is formed during a thermonuclear burst is modulated by several physical processes and the burst oscillation profiles unavoidably carry signatures of these. In order to probe these mechanisms, we examined the amplitude and phase lags of the burst oscillations with energy. We also studied the frequency variation of oscillations during these thermonuclear bursts. We observed that the frequency drifts are more frequent in the cases where the spin frequency is lower. We found that the phase lag of the burst oscillations shows no systematic evolution with energy between the bursts, and also in between different sources. In 7 cases, we do indeed observe lag of soft energy photons, while there are a significant number of cases for which hard lag or no lag is observed.

New Astronomy

We report the results of a long-term spectral and timing study of the first transient magnetar, X... more We report the results of a long-term spectral and timing study of the first transient magnetar, XTE J1810−197 which was discovered in 2003, when its X-ray luminosity increased ≈100 fold. We fit X-ray spectra of all archival X-ray observations using a two-component blackbody model, where the cool component is most likely originating from the whole surface of the neutron star and the hot component is from a much smaller hot spot. We investigate the long-term evolution of the surface emission characteristics via tracing its surface temperature, apparent emitting area and pulsed fraction. We evaluate the pulsed fraction in two energy intervals (< 1.5 keV and >1.5 keV) and show that the XTE J1810−197 exhibits slightly higher pulsed emission at energies above 1.5 keV. We explore the characteristics of an absorption line detected around 1.1 keV. We find that the absorption feature is highly variable and its profile is asymmetric. To accurately represent this feature, we introduced an asymmetric Gaussian profile, and quantified the level of asymmetry of the absorption feature.

Space Science Reviews

Plasma accreted onto the surface of a neutron star can ignite due to unstable thermonuclear burni... more Plasma accreted onto the surface of a neutron star can ignite due to unstable thermonuclear burning and produce a bright flash of X-ray emission called a Type-I X-ray burst. Such events are very common; thousands have been observed to date from over a hundred accreting neutron stars. The intense, often Eddington-limited, radiation generated in these thermonuclear explosions can have a discernible effect on the surrounding accretion flow that consists of an accretion disk and a hot electron corona. Type-I X-ray bursts can there-B N. Degenaar

The Astrophysical Journal

We have compiled the most comprehensive burst sample from magnetar 4U 0142+61, comprising 27 burs... more We have compiled the most comprehensive burst sample from magnetar 4U 0142+61, comprising 27 bursts from its three burst-active episodes in 2011, 2012 and the latest one in 2015 observed with Swift/BAT and Fermi /GBM. Bursts from 4U 0142+61 morphologically resemble typical short bursts from other magnetars. However, 4U 0142+61 bursts are less energetic compared to the bulk of magnetar bursts. We uncovered an extended tail emission following a burst on 2015 February 28, with a thermal nature, cooling over a timescale of several minutes. During this tail emission, we also uncovered pulse peak phase aligned X-ray bursts , which could originate from the same underlying mechanism as that of the extended burst tail, or an associated and spatially coincident but different mechanism.

The Astronomer S Telegram, Nov 1, 2010

ABSTRACT We report Rossi X-ray Timing Explorer data analysis of the Terzan 5 source IGR J17480-24... more ABSTRACT We report Rossi X-ray Timing Explorer data analysis of the Terzan 5 source IGR J17480-2446, which is currently in outburst (ATels #2919, #2920, #2922, #2924, #2929, #2932, #2933, #2935, #2937, #2939, #2946, #2952, #2958, #2974, #3000). Galloway and in &#39;t Zand (ATel #3000) reported that after the 2010 October 13 thermonuclear burst, no other burst up to 2010 October 26 showed significant (&gt;2 sigma confidence) cooling during burst decay.

ABSTRACT A thermonuclear burst has been reported from the RXTE data of the transient neutron star... more ABSTRACT A thermonuclear burst has been reported from the RXTE data of the transient neutron star low-mass X-ray binary IGR J17498-2921 (Atel #3568), which is also a 401 Hz pulsar and went into an outburst in August 2011 (Atels #3551, #3555, #3556, #3558, #3559, #3560, #3561, #3562, #3563, #3601, #3606, #3622, #3638). We report the detection of nine additional bursts from the RXTE data up to September 7, 2011.

Two energetic hard X-ray bursts from the rotation-powered pulsar PSR J1119−6127 recently triggere... more Two energetic hard X-ray bursts from the rotation-powered pulsar PSR J1119−6127 recently triggered the Fermi and Swift space observatories. We have performed in-depth spectral and temporal analyses of these two events. Our extensive searches in both observatories' data for lower luminosity bursts uncovered 10 additional events from the source. We report here on the timing and energetics of the 12 bursts from PSR J1119−6127 during its burst active phase on 2016 July 26 and 28. We also found a spectral softer X-ray flux enhancement in a post-burst episode, which shows evidence of cooling. Here we discuss the implications of these results on the nature of this unusual high-field radio pulsar, which firmly place it within the typical magnetar population.

ABSTRACT We report Rossi X-ray Timing Explorer data analysis of the Terzan 5 source IGR J17480-24... more ABSTRACT We report Rossi X-ray Timing Explorer data analysis of the Terzan 5 source IGR J17480-2446, which is currently in outburst (ATels #2919, #2920, #2922, #2924, #2929, #2932, #2933, #2935, #2937, #2939, #2946, #2952, #2958, #2974, #3000). Galloway and in &#39;t Zand (ATel #3000) reported that after the 2010 October 13 thermonuclear burst, no other burst up to 2010 October 26 showed significant (&gt;2 sigma confidence) cooling during burst decay.

Plasma accreted onto the surface of a neutron star can ignite due to unstable thermonuclear burni... more Plasma accreted onto the surface of a neutron star can ignite due to unstable thermonuclear burning and produce a bright flash of X-ray emission called a Type-I X-ray burst. Such events are very common; thousands have been observed to date from over a hundred accreting neutron stars. The intense, often Eddington-limited, radiation generated in these thermonuclear explosions can have a discernible effect on the surrounding accretion flow that consists of an accretion disk and a hot electron corona. Type-I X-ray bursts can thereB N. Degenaar N.D.Degenaar@uva.nl 1 Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 OHA, UK 2 Anton Pannekoek Institute, University of Amsterdam, Science Park 904, 1098, Amsterdam, The Netherlands 3 School of Physics, Georgia Institute of Technology, Center for Relativistic Astrophysics, Atlanta, GA 30332, USA 4 Istituto Nazionale di Astrofisica, Osservatorio Astronomico di Brera, Via E. Bianchi 46, 23807 Merate, Italy 5 Faculty o...

arXiv: High Energy Astrophysical Phenomena, 2020

The giant flares of soft gamma-ray repeaters (SGRs) have long been proposed to contribute to at l... more The giant flares of soft gamma-ray repeaters (SGRs) have long been proposed to contribute to at least a subsample of the observed short gamma-ray bursts (GRBs). In this paper, we perform a comprehensive analysis of the high-energy data of the recent bright short GRB 200415A, which was located close to the Sculptor galaxy. Our results suggest that a magnetar giant flare provides the most natural explanation for most observational properties of GRB 200415A, including its location, temporal and spectral features, energy, statistical correlations, and high-energy emissions. On the other hand, the compact star merger GRB model is found to have difficulty reproducing such an event in a nearby distance. Future detections and follow-up observations of similar events are essential to firmly establish the connection between SGR giant flares and a subsample of nearby short GRBs.

The Astrophysical Journal, 2021

We report the temporal and spectral analysis of three thermonuclear X-ray bursts from 4U 1608−52,... more We report the temporal and spectral analysis of three thermonuclear X-ray bursts from 4U 1608−52, observed by the Neutron Star Interior Composition Explorer (NICER) during and just after the outburst observed from the source in 2020. In two of the X-ray bursts, we detect secondary peaks 30 and 18 s after the initial peaks. The secondary peaks show a fast rise exponential decay-like shape resembling a thermonuclear X-ray burst. Time-resolved X-ray spectral analysis reveals that the peak flux, blackbody temperature, and apparent emitting radius values of the initial peaks are in agreement with X-ray bursts previously observed from 4U 1608−52, while the same values for the secondary peaks tend toward the lower end of the distribution of bursts observed from this source. The third X-ray burst, which happened during much lower accretion rates, did not show any evidence for a deviation from an exponential decay and was significantly brighter than the previous bursts. We present the proper...

We report the results of a long-term spectral and timing study of the first transient magnetar, X... more We report the results of a long-term spectral and timing study of the first transient magnetar, XTE J1810−197 which was discovered in 2003, when its X-ray luminosity increased ≈100 fold. We fit X-ray spectra of all archival X-ray observations using a two-component blackbody model, where the cool component is most likely originating from the whole surface of the neutron star and the hot component is from a much smaller hot spot. We investigate the long-term evolution of the surface emission characteristics via tracing its surface temperature, apparent emitting area and pulsed fraction. We evaluate the pulsed fraction in two energy intervals (< 1.5 keV and >1.5 keV) and show that the XTE J1810−197 exhibits slightly higher pulsed emission at energies above 1.5 keV. We explore the characteristics of an absorption line detected around 1.1 keV. We find that the absorption feature is highly variable and its profile is asymmetric. To accurately represent this feature, we introduced an...

Giant flares (GFs) are unusual bursts from soft gamma-ray repeaters (SGRs) that release an enormo... more Giant flares (GFs) are unusual bursts from soft gamma-ray repeaters (SGRs) that release an enormous amount of energy in a fraction of a second. The afterglow emission of these SGR-GFs or GF candidates is a highly beneficial means of discerning their composition, relativistic speed, and emission mechanisms. GRB 200415A is a recent GF candidate observed in a direction coincident with the nearby Sculptor galaxy at 3.5 Mpc. In this work, we searched for transient gamma-ray emission in past observations by Fermi-LAT in the direction of GRB 200415A. These observations confirm that GRB 200415A is observed as a transient GeV source only once. A pure pair-plasma fireball cannot provide the required energy for the interpretation of GeV afterglow emission and a baryonic poor outflow is additionally needed to explain the afterglow emission. A baryonic rich outflow is also viable, as it can explain the variability and observed quasi-thermal spectrum of the prompt emission if dissipation is happe...

Accreted matter falling on the surface of the neutron star in a Low Mass X-ray Binary (LMXB) syst... more Accreted matter falling on the surface of the neutron star in a Low Mass X-ray Binary (LMXB) system gives rise to intense X-r ay bursts originating from unstable thermonuclear conflagration and these bursts can be used as a tool to constrain the equation of state. A series o f such Xray bursts along with millihertz (mHz) quasi-periodic osci llat ons (QPOs) at the highest source luminosities were observed during the 2010 outburst of the transient LMXB pulsar IGR J17480–2446. The quite dive rse burst properties compared to typical type-I bursts suggested the m o be the typeII bursts originating from accretion disc instability. We s how that the bursts are indeed of thermonuclear origin and thus confirm the quasi -st ble burning model for mHz QPOs. Various properties of the bursts such as, peak flux, fluence, periodicity and duration, were highly depende nt on the source spectral states and their variation over a large accretion r ate range revealed the evolution of the burning process...

Publications of the Astronomical Society of Australia, 2021

We present the results of our extensive binary orbital motion corrected pulsation search for 13 l... more We present the results of our extensive binary orbital motion corrected pulsation search for 13 low-mass X-ray binaries. These selected sources exhibit burst oscillations in X-rays with frequencies ranging from 45 to 1 122 Hz and have a binary orbital period varying from 2.1 to 18.9 h. We first determined episodes that contain weak pulsations around the burst oscillation frequency by searching all archival Rossi X-ray Timing Explorer data of these sources. Then, we applied Doppler corrections to these pulsation episodes to discard the smearing effect of the binary orbital motion and searched for recovered pulsations at the second stage. Here we report 75 pulsation episodes that contain weak but coherent pulsations around the burst oscillation frequency. Furthermore, we report eight new episodes that show relatively strong pulsations in the binary orbital motion corrected data.

Research in Astronomy and Astrophysics

The Astrophysical Journal, Dec 14, 2017

We have investigated temporal and spectral properties of a large sample of thermonuclear bursts w... more We have investigated temporal and spectral properties of a large sample of thermonuclear bursts with oscillations from eight different sources with spin frequencies varying from 270 to 620 Hz. For our sample we chose those bursts, for which the oscillation is sufficiently strong and of relatively long duration. The emission from the hot-spot that is formed during a thermonuclear burst is modulated by several physical processes and the burst oscillation profiles unavoidably carry signatures of these. In order to probe these mechanisms, we examined the amplitude and phase lags of the burst oscillations with energy. We also studied the frequency variation of oscillations during these thermonuclear bursts. We observed that the frequency drifts are more frequent in the cases where the spin frequency is lower. We found that the phase lag of the burst oscillations shows no systematic evolution with energy between the bursts, and also in between different sources. In 7 cases, we do indeed observe lag of soft energy photons, while there are a significant number of cases for which hard lag or no lag is observed.

New Astronomy

We report the results of a long-term spectral and timing study of the first transient magnetar, X... more We report the results of a long-term spectral and timing study of the first transient magnetar, XTE J1810−197 which was discovered in 2003, when its X-ray luminosity increased ≈100 fold. We fit X-ray spectra of all archival X-ray observations using a two-component blackbody model, where the cool component is most likely originating from the whole surface of the neutron star and the hot component is from a much smaller hot spot. We investigate the long-term evolution of the surface emission characteristics via tracing its surface temperature, apparent emitting area and pulsed fraction. We evaluate the pulsed fraction in two energy intervals (< 1.5 keV and >1.5 keV) and show that the XTE J1810−197 exhibits slightly higher pulsed emission at energies above 1.5 keV. We explore the characteristics of an absorption line detected around 1.1 keV. We find that the absorption feature is highly variable and its profile is asymmetric. To accurately represent this feature, we introduced an asymmetric Gaussian profile, and quantified the level of asymmetry of the absorption feature.

Space Science Reviews

Plasma accreted onto the surface of a neutron star can ignite due to unstable thermonuclear burni... more Plasma accreted onto the surface of a neutron star can ignite due to unstable thermonuclear burning and produce a bright flash of X-ray emission called a Type-I X-ray burst. Such events are very common; thousands have been observed to date from over a hundred accreting neutron stars. The intense, often Eddington-limited, radiation generated in these thermonuclear explosions can have a discernible effect on the surrounding accretion flow that consists of an accretion disk and a hot electron corona. Type-I X-ray bursts can there-B N. Degenaar

The Astrophysical Journal

We have compiled the most comprehensive burst sample from magnetar 4U 0142+61, comprising 27 burs... more We have compiled the most comprehensive burst sample from magnetar 4U 0142+61, comprising 27 bursts from its three burst-active episodes in 2011, 2012 and the latest one in 2015 observed with Swift/BAT and Fermi /GBM. Bursts from 4U 0142+61 morphologically resemble typical short bursts from other magnetars. However, 4U 0142+61 bursts are less energetic compared to the bulk of magnetar bursts. We uncovered an extended tail emission following a burst on 2015 February 28, with a thermal nature, cooling over a timescale of several minutes. During this tail emission, we also uncovered pulse peak phase aligned X-ray bursts , which could originate from the same underlying mechanism as that of the extended burst tail, or an associated and spatially coincident but different mechanism.

The Astronomer S Telegram, Nov 1, 2010

ABSTRACT We report Rossi X-ray Timing Explorer data analysis of the Terzan 5 source IGR J17480-24... more ABSTRACT We report Rossi X-ray Timing Explorer data analysis of the Terzan 5 source IGR J17480-2446, which is currently in outburst (ATels #2919, #2920, #2922, #2924, #2929, #2932, #2933, #2935, #2937, #2939, #2946, #2952, #2958, #2974, #3000). Galloway and in &#39;t Zand (ATel #3000) reported that after the 2010 October 13 thermonuclear burst, no other burst up to 2010 October 26 showed significant (&gt;2 sigma confidence) cooling during burst decay.

ABSTRACT A thermonuclear burst has been reported from the RXTE data of the transient neutron star... more ABSTRACT A thermonuclear burst has been reported from the RXTE data of the transient neutron star low-mass X-ray binary IGR J17498-2921 (Atel #3568), which is also a 401 Hz pulsar and went into an outburst in August 2011 (Atels #3551, #3555, #3556, #3558, #3559, #3560, #3561, #3562, #3563, #3601, #3606, #3622, #3638). We report the detection of nine additional bursts from the RXTE data up to September 7, 2011.

Two energetic hard X-ray bursts from the rotation-powered pulsar PSR J1119−6127 recently triggere... more Two energetic hard X-ray bursts from the rotation-powered pulsar PSR J1119−6127 recently triggered the Fermi and Swift space observatories. We have performed in-depth spectral and temporal analyses of these two events. Our extensive searches in both observatories' data for lower luminosity bursts uncovered 10 additional events from the source. We report here on the timing and energetics of the 12 bursts from PSR J1119−6127 during its burst active phase on 2016 July 26 and 28. We also found a spectral softer X-ray flux enhancement in a post-burst episode, which shows evidence of cooling. Here we discuss the implications of these results on the nature of this unusual high-field radio pulsar, which firmly place it within the typical magnetar population.

We report Rossi X-ray Timing Explorer data analysis of the Terzan 5 source IGR J17480-2446, which... more We report Rossi X-ray Timing Explorer data analysis of the Terzan 5 source IGR J17480-2446, which is currently in outburst (ATels #2919, #2920, #2922, #2924, #2929, #2932, #2933, #2935, #2937, #2939, #2946, #2952, #2958, #2974, #3000). Galloway and in 't Zand (ATel #3000) reported that after the 2010 October 13 thermonuclear burst, no other burst up to 2010 October 26 showed significant (>2 sigma confidence) cooling during burst decay.