K. Mukerjee

Bio: K. Mukerjee is an academic researcher from University of Leicester. The author has contributed to research in topics: Gamma-ray burst & X-ray telescope. The author has an hindex of 9, co-authored 15 publications receiving 4416 citations. Previous affiliations of K. Mukerjee include Tata Institute of Fundamental Research.

The Swift X-ray telescope

Abstract: he Swift Gamma-Ray Explorer is designed to make prompt multiwavelength observations of gamma-ray bursts (GRBs) and GRB afterglows. The X-ray telescope (XRT) enables Swift to determine GRB positions with a few arcseconds accuracy within 100 s of the burst onset. The XRT utilizes a mirror set built for JET-X and an XMM-Newton/EPIC MOS CCD detector to provide a sensitive broad-band (0.2–10 keV) X-ray imager with effective area of > 120 cm2 at 1.5 keV, field of view of 23.6 × 23.6 arcminutes, and angular resolution of 18 arcseconds (HPD). The detection sensitivity is 2×10−14 erg cm−2 s−1 in 104 s. The instrument is designed to provide automated source detection and position reporting within 5 s of target acquisition. It can also measure the redshifts of GRBs with Fe line emission or other spectral features. The XRT operates in an auto-exposure mode, adjusting the CCD readout mode automatically to optimize the science return for each frame as the source intensity fades. The XRT will measure spectra and lightcurves of the GRB afterglow beginning about a minute after the burst and will follow each burst for days or weeks.

The Swift X-ray Telescope

Abstract: The Swift Gamma-Ray Explorer is designed to make prompt multiwavelength observations of Gamma-Ray Bursts (GRBs) and GRB afterglows. The X-ray Telescope (XRT) enables Swift to determine GRB positions with a few arcseconds accuracy within 100 seconds of the burst onset. The XRT utilizes a mirror set built for JET-X and an XMM/EPIC MOS CCD detector to provide a sensitive broad-band (0.2-10 keV) X-ray imager with effective area of > 120 cm^2 at 1.5 keV, field of view of 23.6 x 23.6 arcminutes, and angular resolution of 18 arcseconds (HPD). The detection sensitivity is 2x10^-14 erg cm^-2 s^-1 in 10^4 seconds. The instrument is designed to provide automated source detection and position reporting within 5 seconds of target acquisition. It can also measure the redshifts of GRBs with Fe line emission or other spectral features. The XRT operates in an auto-exposure mode, adjusting the CCD readout mode automatically to optimize the science return for each frame as the source intensity fades. The XRT will measure spectra and lightcurves of the GRB afterglow beginning about a minute after the burst and will follow each burst for days or weeks.

SWIFT XRT point spread function measured at the Panter end-to-end tests

Abstract: SWIFTXRTPointSpreadFunctionmeasuredattheanterend-to-endtestsA.Morettia,S.CampanaG. TagliaferriA.F.Abb eycR.M.AmbrosiL. AngelinighBeardmorec,H.W.BrauningereW.BurkertD.N. BurrowsbM.Capalbid,G.ChincariniaO.Citterioa,G. CusumanofM.J.Freyb ergeP.GiommidG.D.Hartner, J.E.HillbK. Mori,D.MorrisbK.MukerjeecJ.A.NousekJ. Osb orneA.D.T.ShortF.TamburellidD.J.Watsonc,A.ellsaINAFOsservatorio Astronomico di Brera,ItalybPennsylvania StateUniversity,USAcUniversityof Leicester,UKdAgenzia Spaziale Italiana, ItalyeMax-Planck-Institutfur ExtraterrestrischePhysik,GermanyfCNRIstituto diFisica Cosmica edApplicazioni dell' Informatica, ItalygLHEA,GSFC/NASAhUSRAABSTRACTTheSWIFTX{rayTelescop e (XRT) is designed to make astrometric, sp ectroscopic and photometric observa-tions of the X{ray emission from Gamma{ray bursts and their afterglows, in the energy band 0.2-10 keV. Herewe rep ort the results of the analysis ofSWIFTXRTPoint Spread Function (PSF) as measured during the end-to-end calibration campaign at the Panter X{Ray b eam line facility.The analysis comprises the study of thePSF b oth on{axis and o {axis.We compare the lab oratory results with the exp ectations from the ray{tracingsoftwareandfromthemirrormo duletestedasasingleunit.WeshothatmeasuredHEWmeetsmission scienti c requirements.On the basis of the calibration data we build an analytical mo del which is ableto repro duce the PSF as a function of the energy and the p osition within the detector.Keywords:Swift, XRT, PSF1. INTRODUCTIONThe XRT1is a sensitive, autonomous X-ray CCD imaging sp ectrometer designed to measure the ux, sp ectrum,and light curve of GRBs and afterglowover a wide ux range coering more than seven orders of magnitude inux.XRT utilizes the third ight mirror mo dule (FM3) develop ed for the JET{X program2:it consists of 12nested,confo caland coaxial mirror shells having a WolterI con guration.The mirror diameters range from191 mmto300 mm,thenominalfo callengthis 3500 mm,total eldofview isab out40 arcminutes (at50% vignetting level) and the e ectivearea at1.5 keV is165 cm2.The XRT imaging arrayis aMAT-22CCD consisting of 600 x 600 pixels, each40m40m with a nominal plate scale of 2.36 arcseconds p er pixel,whichmakes the e ective eld of view of the system24 arcmin.1The instrumentresponseof 1 counts secSend corresp ondence to moretti@merate.mi.astro.it

The Swift X-Ray Telescope

Abstract: The Swift Gamma-Ray Explorer is designed to make prompt multiwavelength observations of Gamma-Ray Bursts (GRBs) and GRB Afterglows. The X-ray Telescope (XRT) provides key capabilities that permit Swift to determine GRB positions with a few arcseconds accuracy within 100 seconds of the burst onset. The XRT utilizes a superb mirror set built for JET-X and a state-of-the-art XMM/EPIC MOS CCD detector to provide a sensitive broad-band (0.2-10 keV) X-ray imager with effective area of 135 cm2 at 1.5 keV, field of view of 23.6 x 23.6 arcminutes, and angular resolution of 18 arcseconds (HEW). The detection sensitivity is 2x10-14 erg/cm2/s in 104 seconds. The instrument is designed to provide automated source detection and position reporting within 5 seconds of target acquisition. It can also measure redshifts of GRBs for bursts with Fe line emission or other spectral features. The XRT will operate in an auto-exposure mode, adjusting the CCD readout mode automatically to optimize the science return for each frame as the source fades. The XRT will measure spectra and lightcurves of the GRB afterglow beginning about a minute after the burst and will follow each burst for days as it fades from view.

Studies of orbital parameters and pulse profile of the accreting millisecond pulsar XTE J1807-294

Abstract: The accreting millisecond pulsar XTE J1807-294 was observed as a Target of Opportunity (ToO) by XMM-Newton on March 22, 2003 after its discovery on February 21, 2003 by RXTE . The source was detected in its bright phase with an observed average count rate of 33.3 cts s -1 in the EPIC-pn camera in the 0.5–10 keV energy band (3.7 mCrab). Using the earlier established best-fit orbital period of 40.0741 ± 0.0005 min from the RXTE observations and considering a circular binary orbit as first approximation, we derived a value of 4.8 ± 0.1 lt-ms for the projected orbital radius of the binary system and an epoch of the orbital phase of MJD 52 720.67415(16). The barycentric mean spin period of the pulsar was derived as 5.2459427 ± 0.0000004 ms. The pulsar's spin-pulse profile showed a prominent (1.5 ms FWHM ) pulse, with energy and orbital phase dependence in the amplitude and shape. The measured pulsed fraction in four energy bands was found to be 3.1 ± 0.2% (0.5–3.0 keV), 5.4 ± 0.4% (3.0–6.0 keV), 5.1 ± 0.7% (6.0–10.0 keV) and 3.7 ± 0.2% (0.5–10.0 keV), respectively. Studies of spin-profiles with orbital phase and energy showed significant increase in its pulsed fraction during the second observed orbit of the neutron star, gradually declining in the subsequent two orbits, which was associated with sudden but marginal increase in mass accretion. From our investigations of orbital parameters and estimation of other properties of this compact binary system, we conclude that XTE J1807-294 is very likely a candidate for a millisecond radio pulsar.

The Swift Gamma-Ray Burst Mission

Abstract: The Swift mission, scheduled for launch in 2004, is a multiwavelength observatory for gamma-ray burst (GRB) astronomy. It is a first-of-its-kind autonomous rapid-slewing satellite for transient astronomy and pioneers the way for future rapid-reaction and multiwavelength missions. It will be far more powerful than any previous GRB mission, observing more than 100 bursts yr � 1 and performing detailed X-ray and UV/optical afterglow observations spanning timescales from 1 minute to several days after the burst. The objectives are to (1) determine the origin of GRBs, (2) classify GRBs and search for new types, (3) study the interaction of the ultrarelativistic outflows of GRBs with their surrounding medium, and (4) use GRBs to study the early universe out to z >10. The mission is being developed by a NASA-led international collaboration. It will carry three instruments: a newgeneration wide-field gamma-ray (15‐150 keV) detector that will detect bursts, calculate 1 0 ‐4 0 positions, and trigger autonomous spacecraft slews; a narrow-field X-ray telescope that will give 5 00 positions and perform spectroscopy in the 0.2‐10 keV band; and a narrow-field UV/optical telescope that will operate in the 170‐ 600 nm band and provide 0B3 positions and optical finding charts. Redshift determinations will be made for most bursts. In addition to the primary GRB science, the mission will perform a hard X-ray survey to a sensitivity of � 1m crab (� 2;10 � 11 ergs cm � 2 s � 1 in the 15‐150 keV band), more than an order of magnitude better than HEAO 1 A-4. A flexible data and operations system will allow rapid follow-up observations of all types of

Multi-messenger observations of a binary neutron star merger

Abstract: On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of $\sim 1.7\,{\rm{s}}$ with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of ${40}_{-8}^{+8}$ Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 $\,{M}_{\odot }$. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at $\sim 40\,{\rm{Mpc}}$) less than 11 hours after the merger by the One-Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient's position $\sim 9$ and $\sim 16$ days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC 4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta.

The Swift X-ray telescope

Abstract: he Swift Gamma-Ray Explorer is designed to make prompt multiwavelength observations of gamma-ray bursts (GRBs) and GRB afterglows. The X-ray telescope (XRT) enables Swift to determine GRB positions with a few arcseconds accuracy within 100 s of the burst onset. The XRT utilizes a mirror set built for JET-X and an XMM-Newton/EPIC MOS CCD detector to provide a sensitive broad-band (0.2–10 keV) X-ray imager with effective area of > 120 cm2 at 1.5 keV, field of view of 23.6 × 23.6 arcminutes, and angular resolution of 18 arcseconds (HPD). The detection sensitivity is 2×10−14 erg cm−2 s−1 in 104 s. The instrument is designed to provide automated source detection and position reporting within 5 s of target acquisition. It can also measure the redshifts of GRBs with Fe line emission or other spectral features. The XRT operates in an auto-exposure mode, adjusting the CCD readout mode automatically to optimize the science return for each frame as the source intensity fades. The XRT will measure spectra and lightcurves of the GRB afterglow beginning about a minute after the burst and will follow each burst for days or weeks.

The Swift X-ray Telescope

Abstract: The Swift Gamma-Ray Explorer is designed to make prompt multiwavelength observations of Gamma-Ray Bursts (GRBs) and GRB afterglows. The X-ray Telescope (XRT) enables Swift to determine GRB positions with a few arcseconds accuracy within 100 seconds of the burst onset. The XRT utilizes a mirror set built for JET-X and an XMM/EPIC MOS CCD detector to provide a sensitive broad-band (0.2-10 keV) X-ray imager with effective area of > 120 cm^2 at 1.5 keV, field of view of 23.6 x 23.6 arcminutes, and angular resolution of 18 arcseconds (HPD). The detection sensitivity is 2x10^-14 erg cm^-2 s^-1 in 10^4 seconds. The instrument is designed to provide automated source detection and position reporting within 5 seconds of target acquisition. It can also measure the redshifts of GRBs with Fe line emission or other spectral features. The XRT operates in an auto-exposure mode, adjusting the CCD readout mode automatically to optimize the science return for each frame as the source intensity fades. The XRT will measure spectra and lightcurves of the GRB afterglow beginning about a minute after the burst and will follow each burst for days or weeks.

Methods and results of an automatic analysis of a complete sample of Swift-XRT observations of GRBs

Abstract: We present a homogeneous X-ray analysis of all 318 gamma-ray bursts detected by the X-ray telescope (XRT) on the Swift satellite up to 2008 July 23; this represents the largest sample of X-ray GRB data published to date. In Sections 2-3, we detail the methods which the Swift-XRT team has developed to produce the enhanced positions, light curves, hardness ratios and spectra presented in this paper. Software using these methods continues to create such products for all new GRBs observed by the Swift-XRT. We also detail web-based tools allowing users to create these products for any object observed by the XRT, not just GRBs. In Sections 4-6, we present the results of our analysis of GRBs, including probability distribution functions of the temporal and spectral properties of the sample. We demonstrate evidence for a consistent underlying behaviour which can produce a range of light-curve morphologies, and attempt to interpret this behaviour in the framework of external forward shock emission. We find several difficulties, in particular that reconciliation of our data with the forward shock model requires energy injection to continue for days to weeks.