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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"

37518 results found.

  1. GRB 020322 optical observation
  2. GRB020317 : Near IR Observations from Mt Abu Observatory
  3. GRB 020322: Optical Sources and Improved Astrometry
  4. GRB020322, optical observations
  5. GRB 020322: Optical candidate
  6. GRB020322: BeppoSAX/NFI Observations
  7. Bepposax GRB020322 The second springtime BSAX GRB
  8. GRB 020321: Optical observations
  9. GRB 011121: Fourth Epoch of HST Imaging
  10. GRB020317: optical observations
  11. GRB020321 optical observations
  12. GRB020321: BeppoSAX/NFI Observations
  13. GRB020321: a faint BeppoSAX detection
  14. GRB 020317 : KISO Optical Observations
  15. BeppoSAX ALERT: GRB020321, the "Springtime Burst"
  16. GRB020317 (=H1959): Localization by HETE of a Low Fluence GRB
  17. GRB 020305: Optical Observations
  18. GRB020317, optical observations
  19. GRB 020317: Optical observations
  20. GRB 011121: Third HST Epoch
  21. GRB020305: Properties of the Candidate Optical Afterglow
  22. GRB 011121: HST Observations reveal an intermediate-time multicolor
  23. GRB011121, possible supernova association
  24. GRB011130 (XRF011130) Second Epoch Chandra Observations
  25. GRB020305: Subaru Optical Observations
  26. GRB 020305: Optical observations
  27. XRF/GRB 011030 Images
  28. XRF/GRB 011030: Detection of the Probable Host Galaxy
  29. GRB 020305: Candidate optical afterglow
  30. Type Ic SN2002bl (SN/GRB?) Radio Observations
  31. GRB020305: Optical Observations
  32. IPN triangulation of GRB020305 (HETE 1939)
  33. GRB020305 (=H1939): Localization of a GRB by HETE
  34. GRB 020305: Optical observations
  35. HST Imaging of the afterglow and host of GRB 011121
  36. GRB 010921: HST Observations
  37. IPN detection and localization of Cygnus X-1 flares
  38. GRB020127: Further VLA Observations of Possible Counterparts
  39. IPN detection of further SGR1900+14 activity
  40. SGR1900+14 activity
  41. IPN/HETE Detection of Bursts from SGR1900+14
  42. IPN Upper Limits to a GRB Associated With SN2002ap
  43. GRB020124 BVRI field photometry
  44. GRB020127: Comparison of Chandra Epochs and Identification of Possible Counterparts
  45. SN2002ap (SN/GRB?) Echelle spectra
  46. SN2002ap (SN/GRB?) optical spectrographic observations
  47. GRB020127 Optical Observations
  48. SN 2002ap (SN/GRB?)
  49. SN2002ap (SN/GRB?) UBVRI Field Photometry
  50. GRB020127: Chandra Observations and Prospective Counterparts
  51. pre-SN2002ap (SN/GRB?) imaging of M74
  52. SN 2002ap (hypernova / GRB ??): special list on VSNET
  53. Type Ib/c SN2002ap (SN/GRB?)
  54. Type Ib/c SN2002ap (SN/GRB?) Radio Observations
  55. GRB020124, optical observations
  56. GRB020127: Optical observations
  57. GRB 020127, I-band observations starting 3.14-hr after the event
  58. IPN detection of further activity from SGR1806-20
  59. IPN triangulation of GRB020127 (=H1902)
  60. GRB010921 Optical Observations
  61. GRB020127(=H1902): Localization of a Double-Peaked GRB by HETE
  62. GRB020124: Optical observations
  63. VLT observations of GRB 020124: The fading optical/near-infrared afterglow
  64. GRB020124: Optical observations
  65. GRB 020124: Optical observations
  66. GRB 020124 Optical Observations
  67. IPN triangulation of GRB020124 (HETE 1896)
  68. IPN observations of SGR1806-20
  69. GRB 020124: Optical afterglow
  70. GRB020124(=H1896): Localization of a Long GRB by HETE
  71. GRB optical counterpart candidate in GCN 1217 is M dwarf
  72. Possible optical counterpart to a GRB
  73. GRB011212, Optical Observations
  74. GRB 011211: Detection of the Probable Host Galaxy
  75. GRB 011130 and GRB 011212 - Milagro GeV/TeV Observations
  76. GRB 011211, spectrum and optical photometry
  77. GRB 011130: Optical Observations of X-ray and Radio Sources
  78. GRB 011130, Radio/X-ray Comparison
  79. GRB 011212: optical observation at Asiago
  80. GRB 011211: Evidence for an Optical Break
  81. GRB 011211: TNG Spectroscopic Observations
  82. optical follow-up of GRB(XRF) 011211
  83. GRB 011212: optical observation at Oslo (relayed)
  84. GRB 011211: Optical Spectroscopy
  85. GRB 011211, Optical Observations
  86. GRB011212, BVRI field photometry
  87. GRB011211, BVRI field photometry
  88. GRB011212: Optical observations
  89. GRB 011211: BVRi-band photometry
  90. GRB011212 (=H10001): An X-Ray Rich GRB Detected by HETE
  91. Fading of the optical source associated of XRF 011211
  92. GRB 011211 Optical Observations: Likely Afterglow
  93. BeppoSAX Alert: GRB011211(=XRF011211)
  94. GRB 011130: Optical Observations of Chandra Sources
  95. GRB 011130: Optical Observations of Chandra sources
  96. GRB 011130: Magellan spectroscopy
  97. Sub-mm and Centimeter Detections of the Host Galaxy of GRB000418
  98. GRB011130, optical observations
  99. GRB 011130, K band observations
  100. GRB011130, optical observations

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