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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"

6402 results found.

  1. GRB 021004: Optical Observations
  2. GRB021004: Optical Spectroscopy
  3. XRF 020903: Correction to GCN 1560
  4. XRF 020903: VRI observations
  5. GRB020812: optical observations
  6. GRB 020813 multiband optical observations
  7. GRB/XRF 020427, detection of an underlying system with the VLT
  8. SGR-like X-ray Bursts from AXP 1E 2259+586: follow-up
  9. SGR-like Bursts from the AXP 1E 2259+586
  10. GRB 020531/Candidate Redshift
  11. GRB 020418, optical/near-IR observations
  12. GRB 020603, R-band observation
  13. GRB020531, optical observations
  14. HST detection of the likely host galaxy of GRB 020124
  15. XRF020427: Chandra Observations and Candidate X-ray Counterparts
  16. GRB 020418: Optical observations
  17. GRB 020321: Candidate X-ray Counterparts
  18. GRB 020331: Candidate Optical Afterglow
  19. GRB 020331: NIR Observations
  20. GRB 020322: Optical Sources and Improved Astrometry
  21. GRB 020317: Optical observations
  22. GRB020127: Comparison of Chandra Epochs and Identification of Possible Counterparts
  23. GRB 020127, I-band observations starting 3.14-hr after the event
  24. VLT observations of GRB 020124: The fading optical/near-infrared afterglow
  25. GRB optical counterpart candidate in GCN 1217 is M dwarf
  26. GRB 011121: NIR observations, host galaxy?
  27. GRB 011121: Detection of Bright IR Counterpart
  28. Optical observation of SGR 1806-20 at the 6-m SAO telescope
  29. GRB001109, Host Galaxy Spectroscopic Observations
  30. SGR1806-20: Localization by HETE
  31. SGR 1900+14 : RXTE observations
  32. GRB 010222: Keck Spectroscopy
  33. GRB 010222, Decay Slope Confirmed
  34. Redshift of the Optical Transient of GRB010222
  35. GRB010220, Radio and Optical Observations
  36. GRB010214 Optical Observation
  37. GRB 001204: Ks observations
  38. GRB 001212 Optical Observation
  39. GRB 001212 possible OA in 2MASS
  40. GRB 001212 possible OA
  41. GRB 001105, further optical observations
  42. GRB001120, optical observations
  43. Optical/NIR observations of GRB001109
  44. GRB 001109: deep JHK upper limits
  45. GRB 001105, R-band observation
  46. V,R,I band observations of GRB000926
  47. The Likely Optical/Infrared Afterglow of GRB 001011
  48. GRB000911, Radio and Optical observations
  49. SGR 1806-20 burst activity
  50. GRB000630: Optical observations
  51. GRB000615, R-band photometry
  52. GRB 000418: Detection of the Host Galaxy
  53. X-ray Afterglow of GRB 000529
  54. GRB 000528 Optical Observations
  55. BATSE observations of FXT/GRB 000416 = 1SAXJ1715.0-7134
  56. GRB000301C, Radio observations
  57. GRB000301C, Radio observations
  58. GRB 000210: BATSE Observations
  59. BATSE GRB trigger criteria changed
  60. BATSE Observations of GRB000115
  61. GRB 991216: Updated BATSE parameters
  62. IR observations of GRB991216
  63. GRB 991216 Radio Observations
  64. GRB 991208 SAO-RAS Spectroscopy
  65. GRB 991208 Keck Spectroscopy
  66. GRB 991216: Extremely bright BATSE burst
  67. GRB991208, optical observations
  68. GRB991106: BeppoSAX/BATSE results
  69. BeppoSAX NFI Observation of GRB991106
  70. GRB 991105: BATSE Observations
  71. GRB 991106 Optical Observations
  72. GRB991014 BATSE Observations
  73. BATSE GRB trigger criteria
  74. GRB990806: BATSE Observations
  75. Late-time HST/STIS Observations of GRB 990510
  76. X-ray/GRB 1SAX J0835.9+5118, BATSE Observation
  77. GRB 990510: BATSE Observations
  78. GRB 990510 Optical Observations
  79. GRB 990506: BATSE Observations
  80. GRB 990506, Optical Observations
  81. GRB 990506 optical observations
  82. GRB 990506 optical observations
  83. GRB 990316 optical observations
  84. GRB990123, 15-GHz limits
  85. GRB 990123: BATSE Observations
  86. GRB 990123 Optical Follow-up
  87. GRB981220, Optical Observations
  88. GRB 981220:Optical Observations
  89. GRB 981226 - Infrared Observations
  90. GRB 980326/Host Galaxy
  91. GRB 980923 BATSE Observations
  92. GRB980703, Host galaxy multicolor photometry
  93. GRB 980703: BATSE Observations
  94. GRB 980613: BATSE Observations
  95. SGR1900+14
  96. SGR1900+14
  97. GRB980519 BATSE Observations
  98. BATSE on-board GRB trigger change
  99. GRB980425 BATSE observations
  100. GRB980329

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