On the afterglow of the X-ray flash of 2003 July 23: Photometric evidence for an off-axis gamma-ray burst with an associated supernova?

J. P U Fynbo, J. Sollerman, J. Hjorth, F. Grundahl, J. Gorosabel, M. Weidinger, P. Møller, B. L. Jensen, P. M. Vreeswijk, C. Fransson, E. Ramirez-Ruiz, P. Jakobsson, S. F. Jørgensen, C. Vinter, M. I. Andersen, J. M Castro Cerón, A. J. Castro-Tirado, A. S. Fruchter, J. Greiner, C. KouveliotouA. Levan, S. Klose, N. Masetti, H. Pedersen, E. Palazzi, E. Pian, J. Rhoads, E. Rol, T. Sekiguchi, N. R. Tanvir, P. Tristram, A. De Ugarte Postigo, R. A M J Wijers, E. Van Den Heuvel

Research output: Contribution to journalArticle

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Abstract

We present optical and near-infrared follow-up observations of the X-ray flash (XRF) of 2003 July 23. Our observations in the R band cover the temporal range from 4.2 hr to 64 days after the high-energy event. We also present the results of multicolor imaging extending to the K band on three epochs. The light curve of the R-band afterglow the first week after the burst is similar to the light curve for long-duration gamma-ray bursts (GRBs), i.e., a broken power law with a late time slope of α ≈ 2.0 (Fν α t ). Furthermore, the spectral energy distribution (SED) has a power-law (Fν α ν) shape with slope β≈1.0. However, the decay slope at t < 1 day is shallow, consistent with zero. This is in qualitative agreement with the prediction that XRFs are off-axis classical GRBs. After the first week there is a strong bump in the light curve, which peaks at around 16 days. The SED after the peak becomes significantly redder. We discuss the possible interpretations of this bump and conclude that an underlying supernova is the most likely explanation since no other model appears consistent with the evolution of the SED. Finally, we present deep spectroscopy of the burst both in the afterglow and in the bump phase. A firm upper limit of z = 2.3 is placed on the redshift of XRF 030723 from the lack of Lya forest lines in the spectrum of the afterglow. The lack of significant absorption and emission lines in either of the two spectra excludes a spectroscopic redshift determination.

Original languageEnglish (US)
Pages (from-to)962-971
Number of pages10
JournalAstrophysical Journal
Volume609
Issue number2 I
DOIs
StatePublished - Jul 10 2004
Externally publishedYes

Fingerprint

spectral energy distribution
afterglows
gamma ray bursts
light curve
supernovae
flash
slopes
bursts
energy
power law
x rays
extremely high frequencies
X-ray fluorescence
time measurement
near infrared
spectroscopy
decay
predictions
prediction
distribution

Keywords

  • Cosmology: observations
  • Gamma rays: bursts
  • Supernovae: general
  • X-rays: individual (XRF 030723)

ASJC Scopus subject areas

  • Space and Planetary Science

Cite this

Fynbo, J. P. U., Sollerman, J., Hjorth, J., Grundahl, F., Gorosabel, J., Weidinger, M., ... Van Den Heuvel, E. (2004). On the afterglow of the X-ray flash of 2003 July 23: Photometric evidence for an off-axis gamma-ray burst with an associated supernova? Astrophysical Journal, 609(2 I), 962-971. https://doi.org/10.1086/421260

On the afterglow of the X-ray flash of 2003 July 23 : Photometric evidence for an off-axis gamma-ray burst with an associated supernova? / Fynbo, J. P U; Sollerman, J.; Hjorth, J.; Grundahl, F.; Gorosabel, J.; Weidinger, M.; Møller, P.; Jensen, B. L.; Vreeswijk, P. M.; Fransson, C.; Ramirez-Ruiz, E.; Jakobsson, P.; Jørgensen, S. F.; Vinter, C.; Andersen, M. I.; Cerón, J. M Castro; Castro-Tirado, A. J.; Fruchter, A. S.; Greiner, J.; Kouveliotou, C.; Levan, A.; Klose, S.; Masetti, N.; Pedersen, H.; Palazzi, E.; Pian, E.; Rhoads, J.; Rol, E.; Sekiguchi, T.; Tanvir, N. R.; Tristram, P.; De Ugarte Postigo, A.; Wijers, R. A M J; Van Den Heuvel, E.

In: Astrophysical Journal, Vol. 609, No. 2 I, 10.07.2004, p. 962-971.

Research output: Contribution to journalArticle

Fynbo, JPU, Sollerman, J, Hjorth, J, Grundahl, F, Gorosabel, J, Weidinger, M, Møller, P, Jensen, BL, Vreeswijk, PM, Fransson, C, Ramirez-Ruiz, E, Jakobsson, P, Jørgensen, SF, Vinter, C, Andersen, MI, Cerón, JMC, Castro-Tirado, AJ, Fruchter, AS, Greiner, J, Kouveliotou, C, Levan, A, Klose, S, Masetti, N, Pedersen, H, Palazzi, E, Pian, E, Rhoads, J, Rol, E, Sekiguchi, T, Tanvir, NR, Tristram, P, De Ugarte Postigo, A, Wijers, RAMJ & Van Den Heuvel, E 2004, 'On the afterglow of the X-ray flash of 2003 July 23: Photometric evidence for an off-axis gamma-ray burst with an associated supernova?', Astrophysical Journal, vol. 609, no. 2 I, pp. 962-971. https://doi.org/10.1086/421260
Fynbo, J. P U ; Sollerman, J. ; Hjorth, J. ; Grundahl, F. ; Gorosabel, J. ; Weidinger, M. ; Møller, P. ; Jensen, B. L. ; Vreeswijk, P. M. ; Fransson, C. ; Ramirez-Ruiz, E. ; Jakobsson, P. ; Jørgensen, S. F. ; Vinter, C. ; Andersen, M. I. ; Cerón, J. M Castro ; Castro-Tirado, A. J. ; Fruchter, A. S. ; Greiner, J. ; Kouveliotou, C. ; Levan, A. ; Klose, S. ; Masetti, N. ; Pedersen, H. ; Palazzi, E. ; Pian, E. ; Rhoads, J. ; Rol, E. ; Sekiguchi, T. ; Tanvir, N. R. ; Tristram, P. ; De Ugarte Postigo, A. ; Wijers, R. A M J ; Van Den Heuvel, E. / On the afterglow of the X-ray flash of 2003 July 23 : Photometric evidence for an off-axis gamma-ray burst with an associated supernova?. In: Astrophysical Journal. 2004 ; Vol. 609, No. 2 I. pp. 962-971.
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title = "On the afterglow of the X-ray flash of 2003 July 23: Photometric evidence for an off-axis gamma-ray burst with an associated supernova?",
abstract = "We present optical and near-infrared follow-up observations of the X-ray flash (XRF) of 2003 July 23. Our observations in the R band cover the temporal range from 4.2 hr to 64 days after the high-energy event. We also present the results of multicolor imaging extending to the K band on three epochs. The light curve of the R-band afterglow the first week after the burst is similar to the light curve for long-duration gamma-ray bursts (GRBs), i.e., a broken power law with a late time slope of α ≈ 2.0 (Fν α t -α). Furthermore, the spectral energy distribution (SED) has a power-law (Fν α ν-β) shape with slope β≈1.0. However, the decay slope at t < 1 day is shallow, consistent with zero. This is in qualitative agreement with the prediction that XRFs are off-axis classical GRBs. After the first week there is a strong bump in the light curve, which peaks at around 16 days. The SED after the peak becomes significantly redder. We discuss the possible interpretations of this bump and conclude that an underlying supernova is the most likely explanation since no other model appears consistent with the evolution of the SED. Finally, we present deep spectroscopy of the burst both in the afterglow and in the bump phase. A firm upper limit of z = 2.3 is placed on the redshift of XRF 030723 from the lack of Lya forest lines in the spectrum of the afterglow. The lack of significant absorption and emission lines in either of the two spectra excludes a spectroscopic redshift determination.",
keywords = "Cosmology: observations, Gamma rays: bursts, Supernovae: general, X-rays: individual (XRF 030723)",
author = "Fynbo, {J. P U} and J. Sollerman and J. Hjorth and F. Grundahl and J. Gorosabel and M. Weidinger and P. M{\o}ller and Jensen, {B. L.} and Vreeswijk, {P. M.} and C. Fransson and E. Ramirez-Ruiz and P. Jakobsson and J{\o}rgensen, {S. F.} and C. Vinter and Andersen, {M. I.} and Cer{\'o}n, {J. M Castro} and Castro-Tirado, {A. J.} and Fruchter, {A. S.} and J. Greiner and C. Kouveliotou and A. Levan and S. Klose and N. Masetti and H. Pedersen and E. Palazzi and E. Pian and J. Rhoads and E. Rol and T. Sekiguchi and Tanvir, {N. R.} and P. Tristram and {De Ugarte Postigo}, A. and Wijers, {R. A M J} and {Van Den Heuvel}, E.",
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T1 - On the afterglow of the X-ray flash of 2003 July 23

T2 - Photometric evidence for an off-axis gamma-ray burst with an associated supernova?

AU - Fynbo, J. P U

AU - Sollerman, J.

AU - Hjorth, J.

AU - Grundahl, F.

AU - Gorosabel, J.

AU - Weidinger, M.

AU - Møller, P.

AU - Jensen, B. L.

AU - Vreeswijk, P. M.

AU - Fransson, C.

AU - Ramirez-Ruiz, E.

AU - Jakobsson, P.

AU - Jørgensen, S. F.

AU - Vinter, C.

AU - Andersen, M. I.

AU - Cerón, J. M Castro

AU - Castro-Tirado, A. J.

AU - Fruchter, A. S.

AU - Greiner, J.

AU - Kouveliotou, C.

AU - Levan, A.

AU - Klose, S.

AU - Masetti, N.

AU - Pedersen, H.

AU - Palazzi, E.

AU - Pian, E.

AU - Rhoads, J.

AU - Rol, E.

AU - Sekiguchi, T.

AU - Tanvir, N. R.

AU - Tristram, P.

AU - De Ugarte Postigo, A.

AU - Wijers, R. A M J

AU - Van Den Heuvel, E.

PY - 2004/7/10

Y1 - 2004/7/10

N2 - We present optical and near-infrared follow-up observations of the X-ray flash (XRF) of 2003 July 23. Our observations in the R band cover the temporal range from 4.2 hr to 64 days after the high-energy event. We also present the results of multicolor imaging extending to the K band on three epochs. The light curve of the R-band afterglow the first week after the burst is similar to the light curve for long-duration gamma-ray bursts (GRBs), i.e., a broken power law with a late time slope of α ≈ 2.0 (Fν α t -α). Furthermore, the spectral energy distribution (SED) has a power-law (Fν α ν-β) shape with slope β≈1.0. However, the decay slope at t < 1 day is shallow, consistent with zero. This is in qualitative agreement with the prediction that XRFs are off-axis classical GRBs. After the first week there is a strong bump in the light curve, which peaks at around 16 days. The SED after the peak becomes significantly redder. We discuss the possible interpretations of this bump and conclude that an underlying supernova is the most likely explanation since no other model appears consistent with the evolution of the SED. Finally, we present deep spectroscopy of the burst both in the afterglow and in the bump phase. A firm upper limit of z = 2.3 is placed on the redshift of XRF 030723 from the lack of Lya forest lines in the spectrum of the afterglow. The lack of significant absorption and emission lines in either of the two spectra excludes a spectroscopic redshift determination.

AB - We present optical and near-infrared follow-up observations of the X-ray flash (XRF) of 2003 July 23. Our observations in the R band cover the temporal range from 4.2 hr to 64 days after the high-energy event. We also present the results of multicolor imaging extending to the K band on three epochs. The light curve of the R-band afterglow the first week after the burst is similar to the light curve for long-duration gamma-ray bursts (GRBs), i.e., a broken power law with a late time slope of α ≈ 2.0 (Fν α t -α). Furthermore, the spectral energy distribution (SED) has a power-law (Fν α ν-β) shape with slope β≈1.0. However, the decay slope at t < 1 day is shallow, consistent with zero. This is in qualitative agreement with the prediction that XRFs are off-axis classical GRBs. After the first week there is a strong bump in the light curve, which peaks at around 16 days. The SED after the peak becomes significantly redder. We discuss the possible interpretations of this bump and conclude that an underlying supernova is the most likely explanation since no other model appears consistent with the evolution of the SED. Finally, we present deep spectroscopy of the burst both in the afterglow and in the bump phase. A firm upper limit of z = 2.3 is placed on the redshift of XRF 030723 from the lack of Lya forest lines in the spectrum of the afterglow. The lack of significant absorption and emission lines in either of the two spectra excludes a spectroscopic redshift determination.

KW - Cosmology: observations

KW - Gamma rays: bursts

KW - Supernovae: general

KW - X-rays: individual (XRF 030723)

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