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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"

20357 results found.

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

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