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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"

8474 results found.

  1. GRB020305: Properties of the Candidate Optical Afterglow
  2. GRB020305: Subaru Optical Observations
  3. GRB 020305: Optical observations
  4. GRB 020305: Candidate optical afterglow
  5. GRB020127: Comparison of Chandra Epochs and Identification of Possible Counterparts
  6. GRB020127 Optical Observations
  7. IPN detection of further activity from SGR1806-20
  8. GRB optical counterpart candidate in GCN 1217 is M dwarf
  9. GRB011212: Optical observations at Gunma
  10. GRB 011211, spectrum and optical photometry
  11. GRB 011130, Radio/X-ray Comparison
  12. GRB 011212: optical observation at Oslo (relayed)
  13. GRB 011211: BVRi-band photometry
  14. GRB011212 (=H10001): An X-Ray Rich GRB Detected by HETE
  15. GRB 011130, K band observations
  16. GRB011130 (=XRF011130), Optical Observations
  17. GRB011121: UBRI Observations
  18. Optical observation of SGR 1806-20 at the 6-m SAO telescope
  19. GRB 011030 I-band Observations
  20. GRB 011030 K-band Observations
  21. GRB011019: A Faint, X-ray Rich GRB localized by HETE
  22. GRB010921, negative optical observations
  23. Probable SGR or Short Duration GRB Detected by HETE
  24. GCN and HETE status
  25. GRB 010629 Optical Observations
  26. SGR1900+14
  27. Chandra Observations of SGR 1900+14
  28. BeppoSAX GRB: extension of BSAX operations upto April 30, 2002
  29. Optical Observations of GRB 010324
  30. GRB010222 - Optical observation
  31. GRB010222 - Optical observation
  32. GRB 010214, I-band data
  33. GRB 010222
  34. GRB010222 further R-band photometry
  35. GRB010222 further R-band photometry
  36. GRB010220, Optical Observations
  37. GRB 010220: Near-IR Observations
  38. GRB010214 follow-up from Hanle
  39. GRB 010222: Near-IR Observations
  40. GRB010214, candidate optical afterglow
  41. GRB 010214, Optical Observations
  42. GRB010213, Radio Observations
  43. J-Band Observation of GRB 010214.
  44. Possible InfraRed Transient of GRB 010214.
  45. GRB010214 Optical Observation
  46. GRB 010214, optical observations
  47. GRB010213 detected by HETE
  48. HETE Status
  49. GRB010126 Optical Observations
  50. GRB 001204: Ks observations
  51. GRB 001212 possible OA in 2MASS
  52. GRB001204: Optical observations
  53. GRB001120: Gunn-i observations
  54. GRB001120: Optical observations
  55. WSRT 4.8 GHz observations of GRB001109
  56. GRB 001109: deep JHK upper limits
  57. GRB001007: Optical observations
  58. GRB001007, Radio observations
  59. HETE positions added to GCN
  60. GRB 001007, BVR-band observations
  61. GRB000911: VLT infrared observation
  62. GRB000911: optical VLT observations
  63. GRB000926 K'-band Observation
  64. J and K band observations of GRB 000926
  65. GRB000911 Optical Observations
  66. GRB 000926, optical observation by Oksanen (vsnet-grb)
  67. GRB000926: Optical observations
  68. GRB 000926, Optical Observation
  69. GRB000926, radio observations
  70. GRB 000926: Optical candidate
  71. Optical candidate for GRB000926
  72. GRB000911: Corrected coordinates
  73. GRB000911: Sub-millimeter observations
  74. GRB000911: Optical Transient
  75. GRB000911, Radio and Optical observations
  76. GRB000911: Optical observations
  77. GRB000830: Optical observations
  78. Chandra Position of GRB000210
  79. GRB000830: Optical observations
  80. HST/STIS observations of the host galaxy of GRB 980329
  81. GRB 000630: Detection of the Optical Afterglow
  82. GRB000630, Optical Observations
  83. GRB000630, optical observations
  84. GRB000630, optical observations
  85. GRB000630: Optical observations
  86. possible optical counterpart of GRB 000630
  87. GRB000604 - Optical observations
  88. GRB000604, optical observations
  89. X-ray Afterglow of GRB 000529
  90. GRB000529: Optical Observations
  91. GRB000519: Optical observations
  92. GRB 000528 Optical Observations
  93. GRB 000418, Optical observation
  94. GRB 000418, Optical Observation
  95. GRB 000418, optical observation
  96. GRB 000418, Optical Observation
  97. GRB 000418, Optical Observation
  98. GRB 000408, optical observations
  99. GRB000301C - R magnitude lower limit
  100. GRB 000307 optical observations

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