TY - JOUR

T1 - Highly luminous supernovae associated with gamma-ray bursts: II. the luminous blue bump in the afterglow of GRB 140506A

AU - Kann, D.A.

AU - Rossi, A.

AU - Oates, S.R.

AU - Klose, S.

AU - Blazek, M.

AU - Agüí Fernández, J.F.

AU - De Ugarte Postigo, A.

AU - Thöne, C.C.

AU - Schulze, S.

PY - 2024/4/30

Y1 - 2024/4/30

N2 - Context. The supernovae (SNe) associated with gamma-ray bursts (GRBs) are generally seen as a homogeneous population, but at least one exception exists: The highly luminous SN 2011kl associated with the ultra-long GRB 111209A. Such outliers may also exist for more typical GRBs. Aims. Within the context of a systematic analysis of photometric signatures of GRB-Associated SNe, we found an anomalous bump in the late-Time transient following GRB 140506A at redshift z = 0.889. We hereby aim to show this bump is significantly more luminous and blue than usual SNe following GRBs. Methods. We compiled all available data from the literature and added a full analysis of the Swift/UVOT data, which allowed us to trace the light curve from the first minutes all the way to the host galaxy and to construct a broad spectral energy distribution (SED) of the afterglow that extends the previous SED analysis based on ground-based spectroscopy. Results. We find robust evidence of a late-Time bump following the afterglow that shows evidence of a strong color change, with the spectral slope becoming flatter in the blue region of the spectrum. This bump can be interpreted as a luminous SN bump that is spectrally dissimilar to typical GRB-SNe. Correcting it for the large line-of-sight extinction makes the SN associated with GRB 140506A the most luminous detected so far. Even so, it would be in agreement with a luminosity-duration relation of GRB-SNe. Conclusions. While not supported by spectroscopic evidence, it is likely the bump following GRB 140506A is the signature of an SN that is spectrally dissimilar to classical GRB-SNe and more similar to SN 2011kl-while being associated with an average GRB, indicating the GRB-SN population is more diverse than previously thought and can reach luminosities comparable to those of superluminous SNe. © The Authors 2024.

AB - Context. The supernovae (SNe) associated with gamma-ray bursts (GRBs) are generally seen as a homogeneous population, but at least one exception exists: The highly luminous SN 2011kl associated with the ultra-long GRB 111209A. Such outliers may also exist for more typical GRBs. Aims. Within the context of a systematic analysis of photometric signatures of GRB-Associated SNe, we found an anomalous bump in the late-Time transient following GRB 140506A at redshift z = 0.889. We hereby aim to show this bump is significantly more luminous and blue than usual SNe following GRBs. Methods. We compiled all available data from the literature and added a full analysis of the Swift/UVOT data, which allowed us to trace the light curve from the first minutes all the way to the host galaxy and to construct a broad spectral energy distribution (SED) of the afterglow that extends the previous SED analysis based on ground-based spectroscopy. Results. We find robust evidence of a late-Time bump following the afterglow that shows evidence of a strong color change, with the spectral slope becoming flatter in the blue region of the spectrum. This bump can be interpreted as a luminous SN bump that is spectrally dissimilar to typical GRB-SNe. Correcting it for the large line-of-sight extinction makes the SN associated with GRB 140506A the most luminous detected so far. Even so, it would be in agreement with a luminosity-duration relation of GRB-SNe. Conclusions. While not supported by spectroscopic evidence, it is likely the bump following GRB 140506A is the signature of an SN that is spectrally dissimilar to classical GRB-SNe and more similar to SN 2011kl-while being associated with an average GRB, indicating the GRB-SN population is more diverse than previously thought and can reach luminosities comparable to those of superluminous SNe. © The Authors 2024.

KW - Gamma-ray burst: individual: GRB 140506A

KW - Supernovae: general

KW - Curve fitting

KW - Gamma rays

KW - Luminance

KW - Gamma rays bursts

KW - Gamma-ray burst: individual: gamma-ray burst 140506a

KW - Photometrics

KW - Red shift

KW - Spectral energy distribution

KW - Systematic analysis

KW - Time transient

KW - Ultra longs

KW - Supernovae

U2 - 10.1051/0004-6361/202142344

DO - 10.1051/0004-6361/202142344

M3 - Journal article

VL - 684

JO - Astronomy and Astrophysics

JF - Astronomy and Astrophysics

SN - 0004-6361

M1 - A164

ER -