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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"

19863 results found.

  1. GRB 020531, INT+WFC deep optical upper limits
  2. GRB020405: polarimetric observations
  3. GRB 020531, simultaneous optical observations
  4. GRB020531: Second epoch Chandra observations
  5. GRB020604, optical observations
  6. GRB020604, BVRcIc field photometry
  7. GRB020603, BVRcIc field observations
  8. GRB020531, BVRcIc field photometry
  9. GRB020531 Optical Observations
  10. GRB020531: Observations with the Chandra X-ray Observatory
  11. IPN triangulation of GRB020603 (possible short/hard GRB)
  12. GRB020531, optical observations
  13. GRB020531: optical observations
  14. GRB020531(=H2042): Optical Observations
  15. GRB020531(=H2042): Optical Observations
  16. GRB020525, optical observations
  17. HETE Observations of GX354-0 (= MXB1728-34, so-called "Slow
  18. XRF020427: Chandra Identification of a Likely X-ray Counterpart
  19. GRB020405 field photometry at ESO
  20. GRB(XRF) 020427: X-ray afterglow with BeppoSAX
  21. GRB020321 : Optical observations.
  22. XRF 020427
  23. The end of BSAX GRB activities
  24. GRB 020410, Radio Observations
  25. GRB 020124: Optical observations
  26. IPN triangulation of GRB020418
  27. GRB020405: VLT observations of the OT environment
  28. IPN triangulation of GRB020413
  29. GRB 020409: No Evidence for an Optical Afterglow
  30. GRB 020331 Kyoto observation on March 31
  31. GRB 020409: Optical observations
  32. X-ray afterglow of GRB020321
  33. GRB020331 optical observations with RIMOTS
  34. GRB020124 optical observations with RIBOTS/RIMOTS
  35. GRB 020321: Candidate X-ray Counterparts
  36. GRB020406(?), optical observations
  37. GRB020405, Radio Observations
  38. GRB 020405, U-band observations
  39. GRB011212: Optical Observations
  40. GRB020331 NIR observation at KPNO (re-submission)
  41. GRB02033 NIR observation at KPNO
  42. GRB020331 field photometry
  43. GRB 020331, NIR observations
  44. GRB020331(=H1963): The "Easter" Burst Detected by HETE
  45. GRB 020322: BeppoSAX observations of the X-ray afterglow
  46. GRB011211: HST Observations of Optical Afterglow and Host Galaxy
  47. Near-Infrared Observations of GRB020322 at TIRGO
  48. GRB 020322: Optical Observations
  49. GRB020127: Proposed Host Galaxy Detection and Identification of Afterglow
  50. GRB 020321: Optical observations
  51. GRB020317 BVRI field photometry
  52. GRB011211 revised BVRI field photometry
  53. GRB020305 BVRI field photometry
  54. GRB020322 BVRI field photometry
  55. GRB020317 : Near IR Observations from Mt Abu Observatory
  56. GRB 020322: Optical Sources and Improved Astrometry
  57. GRB 011121: Fourth Epoch of HST Imaging
  58. GRB020317: optical observations
  59. GRB020321 optical observations
  60. GRB020321: a faint BeppoSAX detection
  61. GRB 020317 : KISO Optical Observations
  62. GRB 020305: Optical Observations
  63. GRB020317, optical observations
  64. GRB 020317: Optical observations
  65. GRB020305: Properties of the Candidate Optical Afterglow
  66. GRB 011121: HST Observations reveal an intermediate-time multicolor
  67. GRB011121, possible supernova association
  68. GRB011130 (XRF011130) Second Epoch Chandra Observations
  69. XRF/GRB 011030: Detection of the Probable Host Galaxy
  70. GRB020305, optical observations
  71. HST Imaging of the afterglow and host of GRB 011121
  72. GRB 010921: HST Observations
  73. IPN detection and localization of Cygnus X-1 flares
  74. SGR1900+14 activity
  75. IPN/HETE Detection of Bursts from SGR1900+14
  76. IPN Upper Limits to a GRB Associated With SN2002ap
  77. GRB020124 BVRI field photometry
  78. GRB020127: Palomar and VLA Observations of Possible Counterparts
  79. GRB020127: Comparison of Chandra Epochs and Identification of Possible Counterparts
  80. SN2002ap (SN/GRB?) Echelle spectra
  81. GRB020127 Optical Observations
  82. SN2002ap (SN/GRB?) UBVRI Field Photometry
  83. GRB020127: Chandra Observations and Prospective Counterparts
  84. pre-SN2002ap (SN/GRB?) imaging of M74
  85. GRB020124, optical observations
  86. GRB020127: Optical observations
  87. GRB 020127, I-band observations starting 3.14-hr after the event
  88. GRB010921 Optical Observations
  89. GRB020127(=H1902): Localization of a Double-Peaked GRB by HETE
  90. GRB020124: Optical observations
  91. GRB 020124: Optical observations
  92. Possible optical counterpart to a GRB
  93. GRB011212, Optical Observations
  94. Optical polarization observations for GRB011211
  95. GRB 011130 and GRB 011212 - Milagro GeV/TeV Observations
  96. GRB 011130: Optical Observations of X-ray and Radio Sources
  97. GRB 011130, Radio/X-ray Comparison
  98. GRB 011212: optical observation at Asiago
  99. GRB 011211: Evidence for an Optical Break
  100. GRB 011212: optical observation at Oslo (relayed)

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