Timing Offset Calibration of CZTI instrument aboard ASTROSAT

Abstract

The radio as well as the high energy emission mechanism in pulsars is yet not understood properly. A multi-wavelength study is likely to help in better understanding of such processes. The first Indian space-based observatory, ASTROSAT, has five instruments aboard, which cover the electromagnetic spectrum from infra-red (1300 $\mathring{A}$) to hard X-ray (380 KeV). Cadmium Zinc Telluride Imager (CZTI), one of the five instruments is a hard X-ray telescope functional over an energy range of 20-380 KeV. We aim to estimate the timing offset introduced in the data acquisition pipeline of the instrument, which will help in time alignment of high energy time series with those from two other ground-based observatories, viz. the Giant Meterwave Radio Telescope (GMRT) and the Ooty Radio Telescope (ORT). PSR B0531+21 is a well-studied pulsar with nearly aligned radio and hard X-ray pulse profiles. We use simultaneous observations of this pulsar with the ASTROSAT, the ORT and the GMRT. The pulsar was especially observed using the ORT with almost daily cadence to obtain good timing solutions. We also supplement the ORT data with archival FERMI data for estimation of timing noise. The timing offset of ASTROSAT instruments was estimated from fits to arrival time data at the ASTROSAT and the radio observatories. We estimate the offset between the GMRT and the ASTROSAT-CZTI to be -4716 $\pm$ 50 $\mu s$. The corresponding offset with the ORT was -29639 $\pm$ 50 $\mu s$. The offsets between the GMRT and Fermi-LAT -5368 $\pm$ 56 $\mu s$. (Abridged)

arXiv comment6 pages, 5 figures, 2 tables, Revised and Updated, accepted for publication in A&A

References in corpus (14)

• TEMPO2, a new pulsar timing package. I: Overview
• PSRCHIVE and PSRFITS An Open Approach to Radio Pulsar Data Storage and Analysis
• The First Fermi Large Area Telescope Catalog of Gamma-ray Pulsars
• Precise Gamma-Ray Timing and Radio Observations of 17 Fermi Gamma-Ray Pulsars
• Radio Emission Signatures in the Crab Pulsar
• Extended Acceleration in Slot Gaps and Pulsar High-Energy Emission
• Gamma-Ray Pulsars: Beaming Evolution, Stats and Unident. EGRET Sources
• Absolute Timing of the Crab Pulsar with RXTE
• Absolute timing with IBIS, SPI and JEM-X aboard INTEGRAL
• Characterization of the Crab Pulsar's Timing Noise
• Radio and X-ray Observations of PSR B0540-69
• Recent glitches detected in the Crab pulsar
• PONDER - A Real time software backend for pulsar and IPS observations at the Ooty Radio Telescope
• Chandra Phase-Resolved Spectroscopy of the High Magnetic Field Pulsar B1509-58

Cited by in corpus (2)

• AstroSat-CZTI as a hard X-ray Pulsar Monitor
• Absolute Time Calibration of LAXPC aboard AstroSat