Luminosity correlations for gamma-ray bursts and implications for their prompt and afterglow emission mechanisms

Abstract

We present the relation between the ($z-$ and $k-$corrected) spectral lags, $\tau$, for the standard Swift energy bands 50-100 keV and 100-200 keV and the peak isotropic luminosity, $L_{\mathrm{iso}}$ (a relation reported first by Norris et al.), for a subset of 12 long Swift GRBs taken from a recent study of this relation by Ukwatta et al. The chosen GRBs are also a subset of the Dainotti et al. sample, a set of Swift GRBs of known redshift, employed in establishing a relation between the (GRB frame) luminosity, $L_X$, of the shallow (or constant) flux portion of the typical XRT GRB-afterglow light curve and the (GRB frame) time of transition to the normal decay rate, $T_{\mathrm{brk}}$. We also present the $L_X-T_{\mathrm{brk}}$ relation using only the bursts common in the two samples. The two relations exhibit a significant degree of correlation ($\rho =-0.65$ for the $L_{\mathrm{iso}}-\tau$ and $\rho =-0.88$ for the $L_X-T_{\mathrm{brk}}$ relation) and have surprisingly similar best-fit power law indices ($-1.19\pm 0.17$ for $L_{\mathrm{iso}}-\tau$ and $-1.10\pm 0.03$ for $L_X-T_{\mathrm{brk}}$). Even more surprisingly, we noted that although $\tau$ and $T_{\mathrm{brk}}$ represent different GRB time variables, it appears that the first relation ($L_{\mathrm{iso}}-\tau$) extrapolates into the second one for timescales $\tau \simeq T_{\mathrm{brk}}$. This fact suggests that these two relations have a common origin, which we conjecture to be kinematic. This relation adds to the recently discovered relations between properties of the prompt and afterglow GRB phases, indicating a much more intimate relation between these two phases than hitherto considered.

References in corpus (4)

• The Hubble Diagram to Redshift >6 from 69 Gamma-Ray Bursts
• A time - luminosity correlation for Gamma Ray Bursts in the X - rays
• Correlations Between Lag, Luminosity, and Duration in Gamma-ray Burst Pulses
• Study of possible systematics in the L*X - Ta* correlation of Gamma Ray Bursts

Cited by in corpus (13)

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• Selection effects in Gamma Ray Bursts correlations: consequences on the ratio between GRB and star formation rates
• Gamma Ray Burst Prompt correlations
• KAT-7 Science Verification: Using HI Observations of NGC 3109 to Understand its Kinematics and Mass Distribution
• A comprehensive analysis of Fermi Gamma-Ray Burst Data: IV. Spectral lag and Its Relation to Ep Evolution
• Gamma-Ray Bursts: Temporal Scales and the Bulk Lorentz Factor
• A New Correlation Between GRB X-Ray Flares And The Prompt Emission
• The supercritical pile gamma-ray burst model: The GRB afterglow steep-decline-and-plateau phase
• Determination of Cosmological Parameters from Gamma Ray Burst Characteristics and Afterglow Correlations
• The statistics of BAT-to-XRT flux ratio in GRB: Evidence for a characteristic value and its implications
• Applying models of pulsar wind nebulae to explain X-ray plateaux following short gamma-ray bursts