False outliers of the Ep,i - Eiso correlation?

Abstract

Context. In the context of an in-depth understanding of GRBs and their possible use in cosmology, some important correlations between the parameters that describe their emission have been discovered, among which the "Ep,i-Eiso" correlation is the most studied. Because of this, it is fundamental to shed light on the peculiar behaviour of a few events, namely GRB 980425 and GRB 031203, that appear to be important outliers of the Ep,i-Eiso correlation. Aims. In this paper we investigate if the locations of GRB 980425 and GRB 031203, the two (apparent) outliers of the correlation, may be due to an observational bias caused by the lacking detection of the soft X-ray emissions associated with these GRBs, from respectively the BATSE detector on-board the Compton Gamma-Ray Observer and INTEGRAL, that were operating at the epoch of the observations. We analyse the observed emission of other similar sub-energetic bursts (GRBs 060218, 100316D and 161219B) observed by Swift and whose integrated emissions match the Ep,i-Eiso relation. We simulate their integrated and time-resolved emissions as would have been observed by the same detectors that observed GRB 980425 and GRB 031203, aimed at reconstructing the light curve and spectra of these bursts. Results. If observed by old generation instruments, GRB 060218, 100316D and 161219B would appear as outliers of the Ep,i-Eiso relation, while if observed with Swift or WFM GRB 060218 would perfectly match the correlation. We also note that the instrument BAT alone (15-150 keV) actually measured 060218 as an outlier. Conclusions. We suggest that if GRB 980425 and GRB 031203 would have been observed by Swift and by eXTP they may have matched the Ep,i-Eiso relation. This provides strong support to the idea that instrumental biases can make some events in the lower-left corner of the Ep,i-Eiso plane appearing as outliers of the "Amati relation".

arXiv comment14 pages, 23 figures, 8 tables, Abstract reduced in this form to match its requirements

References in corpus (38)

• On the Absorption of X-rays in the Interstellar Medium
• The Swift X-ray Telescope
• Discovery of the peculiar supernova 1998bw in the error box of GRB980425
• The Supernova -- Gamma-Ray Burst Connection
• The Burst Alert Telescope (BAT) on the Swift MIDEX Mission
• Intrinsic spectra and energetics of BeppoSAX Gamma-Ray Bursts with known redshifts
• Evidence for a Canonical GRB Afterglow Light Curve in the Swift/XRT Data
• The shock break-out of GRB 060218/SN 2006aj
• GRB Formation Rates inferred from the Spectral Peak Energy - Luminosity Relation
• The collimation--corrected GRB energies correlate with the peak energy of their $\nu F_{\nu }$ spectrum
• An optical supernova associated with the X-ray flash XRF 060218
• The Ep,i - Eiso correlation in GRBs: updated observational status, re-analysis and main implications
• The Complete Spectral Catalog of Bright BATSE Gamma-Ray Bursts
• The Hubble Diagram to Redshift >6 from 69 Gamma-Ray Bursts
• Measuring the cosmological parameters with the Ep,i-Eiso correlation of Gamma-Ray Bursts
• A neutron-star-driven X-ray flash associated with supernova SN 2006aj
• Model-Independent Multi-Variable Gamma-Ray Burst Luminosity Indicator and Its Possible Cosmological Implications
• Panchromatic study of GRB 060124: from precursor to afterglow
• On the Rates of Gamma Ray Bursts and Type Ib/c Supernovae
• A time - luminosity correlation for Gamma Ray Bursts in the X - rays
• Discovery of the nearby long, soft GRB 100316D with an associated supernova
• The Large Observatory for X-ray Timing (LOFT)
• GRB060218: A Relativistic Supernova Shock Breakout
• Prompt and delayed emission properties of Gamma-Ray Bursts observed with BeppoSAX
• The Integral Burst Alert System (IBAS)
• The Highly Energetic Expansion of SN2010bh Associated with GRB 100316D
• An Interpretation of the $h{\nu }_{peak}$ - $E_{iso}$ Correlation for GRB
• The signature of the central engine in the weakest relativistic explosions: GRB100316D
• Measuring cosmological parameters with Gamma-Ray Bursts
• An Off-Axis Model for GRB 031203
• GRB 161219B / SN 2016jca: A low-redshift gamma-ray burst supernova powered by radioactive heating
• Are GRB 980425 and GRB 031203 real outliers or twins of GRB 060218?
• New measurements of ${\Omega }_m$ from gamma-ray bursts
• A search for thermal X-ray signatures in Gamma-Ray Bursts I: Swift bursts with optical supernovae
• A universal scaling for short and long gamma-ray bursts: E_{X,iso}-E_{gamma,iso}-E_{pk}
• The soft X-ray blast in the apparently sub-luminous GRB 031203
• Spectral catalogue of bright gamma-ray bursts detected with the BeppoSAX/GRBM
• The LOFT contribution to GRB science

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• New JWST redshifts for the host galaxies of CDF-S XT1 and XT2: understanding their nature
• Unveiling the Universe with Emerging Cosmological Probes
• A Global Photoionization Response to Prompt Emission and Outliers: Different Origin of Long Gamma-ray Bursts?
• Tale of GRB 171010A/SN 2017htp and GRB 171205A/SN 2017iuk: Magnetar origin?