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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"

2797 results found.

  1. IPN triangulation of GRB020914 - clarification and additional information
  2. IPN triangulation of GRB020910
  3. IPN GCN Circulars now to be issued without restriction
  4. GRB 020813 : HST observations
  5. GRB020813: Magellan BVRI Photometry
  6. GRB020813: High-Resolution Optical Observations
  7. GRB020813: optical observations; possible host galaxy
  8. GRB020812: optical observations
  9. IPN triangulation of GRB020813
  10. GRB020812: possible afterglow candidate
  11. GRB020812: possible afterglow candidate
  12. GRB 020813 Afterglow Observations; Possible break
  13. GRB 020410: Discovery of Probable OT by HST
  14. IPN triangulation of GRB020706
  15. Gemini IR Detection of AXP 1E 2259+586 Post-Burst
  16. Fading Optical Source in the Field of GRB020531
  17. GRB 020531, simultaneous optical observations
  18. GRB020531 Optical observations with TAROT
  19. GRB020531 Optical observations with TAROT
  20. IPN triangulation of GRB020604
  21. Correction to IPN triangulation of GRB020603 (possible short/hard burst)
  22. IPN triangulation of GRB020603 (possible short/hard GRB)
  23. GRB 020531 optical observations with TAROT
  24. IPN detection of possible bursts from SGR1806-20
  25. GRB020427 BeppoSAX NFI Observation
  26. GRB020405: VLT observations of the OT environment
  27. GRB020405: predicted break
  28. April 11 BeppoSAX event (GRB020411) is likely not a GRB
  29. BeppoSAX ALERT: possible GRB020411
  30. GRB020406(?), optical observations
  31. GRB020410, optical observations
  32. BeppoSAX ALERT: possible GRB020410
  33. Fading Optical Afterglow and Possible Host Galaxy of GRB 020405
  34. GRB 020321, Radio Observations
  35. GRB020321: BeppoSAX/NFI Observations
  36. GRB 020317: Optical observations
  37. GRB 011121: HST Observations reveal an intermediate-time multicolor
  38. GRB011121, possible supernova association
  39. GRB020127: Further VLA Observations of Possible Counterparts
  40. GRB020127: Palomar and VLA Observations of Possible Counterparts
  41. GRB020127: Comparison of Chandra Epochs and Identification of Possible Counterparts
  42. SN 2002ap (SN/GRB?)
  43. Type Ib/c SN2002ap (SN/GRB?) Radio Observations
  44. VLT observations of GRB 020124: The fading optical/near-infrared afterglow
  45. GRB 020124 Optical Observations
  46. GRB optical counterpart candidate in GCN 1217 is M dwarf
  47. Possible optical counterpart to a GRB
  48. GRB011130 (=XRF011130): Scheduled Target of Opportunity
  49. GRB 011130: Magellan spectroscopy
  50. GRB011130, optical observations
  51. GRB 011121: J-band observations
  52. GRB 011121: HST Scheduled
  53. GRB011121: fainter still
  54. GRB011121: continued decay
  55. GRB011121: possible redshift, continued decay
  56. GRB011121: fading behavior
  57. GRB011121: possible optical counterpart
  58. GRB 011030 I-band Observation
  59. GRB 011030, WSRT radio observations
  60. BeppoSAX ALERT: Possible X-ray rich GRB011030
  61. GRB 010921: Possible supernova component
  62. GRB010921: Spectroscopy of the Host Galaxy
  63. GRB010923(=H1764): A Short Duration GRB Detected by HETE
  64. IPN triangulation of GRB010921 (=H1761)
  65. GCN and HETE status
  66. GRB010629: Optical Observations
  67. Possible burst from SGR1806-20
  68. IPN triangulation of GRB010613
  69. HETE Fully-Automated GCN Notices
  70. GRB010214, optical observations
  71. SGR1900+14
  72. Possible precursor to the SGR1900+14 giant burst
  73. Further Optical Observations of GRB 010324
  74. GRB 010222, Optical Observations
  75. Sub-millimeter Excess/GRB 010222
  76. GRB010222: R-band data
  77. GRB010222, possible increase of optical decay slope
  78. GRB010222: Optical Observations
  79. GRB010222: possible optical counterpart
  80. GRB010222
  81. GRB 010214, Optical Observations
  82. GRB010214, Radio Observations
  83. GRB010214, optical observations
  84. Possible InfraRed Transient of GRB 010214.
  85. GRB010126 optical observations
  86. IPN TRIANGULATION OF GRB010126
  87. GRB 001212 Optical Observation
  88. GRB 001212 possible OA in 2MASS
  89. GRB 001212 possible OA
  90. Confirmation of IPN position for GRB001204
  91. Optical/NIR observations of GRB001109
  92. GRB 001018, Possible Radio Afterglow
  93. HETE positions added to GCN
  94. GRB000926 - Optical observations
  95. "Snapshot" afterglow IDs and GRB 000830
  96. IPN localization of GRB000730B
  97. GRB 990510: Possible detection of a host galaxy
  98. possible optical counterpart of GRB 000630
  99. GRB990308, HST/STIS observations of the host galaxy
  100. GRB000615, further R-band photometry

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