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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

32494 results found.

  1. Possible GRB 040903 - further analysis
  2. GRB 040827 - Radio Observations
  3. XMM-Newton Images of GRB 040827
  4. GRB040825A: Optical observations
  5. GRB040825A: Optical observations
  6. GRB 040827: optical and NIR observations at the VLT
  7. GRB 040827: UKIRT - 2nd epoch K-band imaging
  8. GRB 040827: 2nd epoch of Magellan K-band imaging
  9. GRB 040827: K imaging - no evidence of variability
  10. GRB 040827: Detection of NIR afterglow
  11. GRB 040827: Possible detection of optical afterglow
  12. GRB 040827: RTT150 optical observations
  13. MASTER: GRB040827 possible OT
  14. GRB 040825B: Optical observations
  15. GRB040827 optical observations
  16. GRB 040827 - Refined position
  17. GRB040825B, BVRcIc field photometry
  18. GCN GRB OBSERBATION REPORT
  19. GRB040825B: optical observations
  20. GRB040825B (=H3510): An XRF Localized in Real Time by HETE
  21. GRB040825B: Correction to GCN 2657
  22. XRF040812: possible afterglow second Chandra observation
  23. GRB 040812: Second epoch CXO Observations
  24. XRF040812: GMRT observations
  25. XRF 040812: optical observation at VLT
  26. GRB 040812: Optical counterparts of CXO sources
  27. XRF040812: possible afterglow
  28. CXO observation of GRB 040812
  29. IPN/HETE localizations of GRB040810 (=H3489)
  30. GRB 040812: Keck and LCO optical observations
  31. GRB 040812: Keck and LCO observations
  32. GRB 040812: radio observations
  33. GRB040812, optical/IR observations
  34. XRF040701: Optical Observations at ESO
  35. IPN/HETE triangulation of GRB040802 (=H3485)
  36. GRB 040730, infrared observations
  37. GRB 040730: Optical observations
  38. Ongoing activity of SGR 1806-20
  39. GRB040624: optical monitoring at TNG
  40. XRF 040701 - optical observations of the decaying Chandra source
  41. XRF040701: Second-Epoch Chandra Observations
  42. XRF040701: VLA Observations
  43. XRF040701: Magellan Spectroscopy of Chandra Source #2 Associated Galaxy
  44. XRF040701: First-Epoch Chandra Observations
  45. GRB040709 J,H-band observations
  46. GRB040624, optical observations
  47. XRF 040701, optical observations
  48. GRB 040624: optical observations
  49. Optical Observations of GRB040624
  50. GRB 040624: optical observations at TNG and VLT
  51. GRB 040624: R-band observations
  52. GRB 040624, optical observations
  53. GRB 030329: Rebrightening of hyperluminal ejecta.
  54. IPN Summary of SGR1806-20 Activity in 2004
  55. GRB040511: Retraction of redshift identification
  56. SGR 1806-20: no IR variability of the proposed counterparts
  57. MASTER:HETE Alert 3259 (SRG1806-20) optical observation
  58. Activivty of SGR 1806-20
  59. GRB 040511, very fast decay?
  60. GRB 030324: Detection and Color of Host Galaxy
  61. GRB 040511: NIR observations with REM
  62. GRB040511: Redshift identifcation
  63. GRB 040511: Optical limit
  64. GRB040511: Candidate optical/NIR afterglow
  65. GRB 040511: ROTSE-III Rapid Optical Upper Limits
  66. GRB 040511: Second Epoch Optical Observations
  67. GRB 040511: Optical observations
  68. GRB 040511: Optical Observations
  69. GRB040511: Optical Observations
  70. GRB040511: Optical Observations
  71. GRB and XRF on April 27, 2004. Detection by Konus-Wind and Helicon (Coronas-F)
  72. IPN triangulation of GRB040425 (=H3183)
  73. On Line Availability of Archival HETE Fregate Data and Lightcurves
  74. GRB040422, optical observations at Loiano
  75. GRB 040422: ROTSE-IIIb Prompt Optical Limits
  76. GRB040422, BVRcIc field calibration
  77. GRB040422: optical and NIR observations at the VLT
  78. GRB 040403, deep optical observations
  79. HETE/IPN localization of GRB040403A (=H3143, a long burst) and GRB040403B(=H3144, a short/hard burst)
  80. GRB 040403: Optical Observations
  81. GRB 040403 Optical Observations
  82. GRB 040403: Optical observations
  83. GRB 040403: optical observations
  84. GRB 040403: Optical Observations
  85. Summary of recent bursts from SGR 1806-20 detected by INTEGRAL
  86. GRB040323: NIR Observations and Variable Object
  87. GRB 040319 (=H3128): An X-Ray-Rich GRB Localized by the HETE-2 WXM and SXC
  88. GRB 040323, a dark GRB ?
  89. GRB040223: Deep NIR NTT data re-analysis
  90. GRB 040223: XMM-Newton results
  91. GRB040223, improved XMM position
  92. GRB 031203: spectoscopic evidence for a 1998bw-like SN
  93. GRB 031203, possible supernova
  94. IBAS results on a burst from SGR1806-20
  95. GRB 040228 Optical observations
  96. IPN triangulation of GRB040228 (H3066, H3067)
  97. GRB 040228 (=H3066?,=H3067?): A Long GRB Localized by the HETE-2 WXM
  98. GRB 040223: Deep NIR NTT observations
  99. GRB 040223 : Optical observation (non-detection)
  100. XMM-Newton Images of GRB 040223

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