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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"

20358 results found.

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

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