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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"

6791 results found.

  1. GRB 020603, R-band observation
  2. GRB020531, optical observations
  3. HST detection of the likely host galaxy of GRB 020124
  4. XRF020427: Chandra Observations and Candidate X-ray Counterparts
  5. GRB 020418: Optical observations
  6. GRB 020321: Candidate X-ray Counterparts
  7. GRB 020331: Candidate Optical Afterglow
  8. GRB 020331: NIR Observations
  9. GRB 020322: Optical Sources and Improved Astrometry
  10. GRB 020317: Optical observations
  11. GRB020127: Comparison of Chandra Epochs and Identification of Possible Counterparts
  12. GRB 020127, I-band observations starting 3.14-hr after the event
  13. VLT observations of GRB 020124: The fading optical/near-infrared afterglow
  14. GRB optical counterpart candidate in GCN 1217 is M dwarf
  15. GRB 011121: NIR observations, host galaxy?
  16. GRB 011121: Detection of Bright IR Counterpart
  17. Optical observation of SGR 1806-20 at the 6-m SAO telescope
  18. GRB001109, Host Galaxy Spectroscopic Observations
  19. SGR1806-20: Localization by HETE
  20. SGR 1900+14 : RXTE observations
  21. GRB 010222: Keck Spectroscopy
  22. GRB 010222, Decay Slope Confirmed
  23. Redshift of the Optical Transient of GRB010222
  24. GRB010220, Radio and Optical Observations
  25. GRB010214 Optical Observation
  26. GRB 001204: Ks observations
  27. GRB 001212 Optical Observation
  28. GRB 001212 possible OA in 2MASS
  29. GRB 001212 possible OA
  30. GRB 001105, further optical observations
  31. GRB001120, optical observations
  32. Optical/NIR observations of GRB001109
  33. GRB 001109: deep JHK upper limits
  34. GRB 001105, R-band observation
  35. V,R,I band observations of GRB000926
  36. The Likely Optical/Infrared Afterglow of GRB 001011
  37. GRB000911, Radio and Optical observations
  38. SGR 1806-20 burst activity
  39. GRB000630: Optical observations
  40. GRB000615, R-band photometry
  41. GRB 000418: Detection of the Host Galaxy
  42. X-ray Afterglow of GRB 000529
  43. GRB 000528 Optical Observations
  44. BATSE observations of FXT/GRB 000416 = 1SAXJ1715.0-7134
  45. GRB000301C, Radio observations
  46. GRB000301C, Radio observations
  47. GRB 000210: BATSE Observations
  48. BATSE GRB trigger criteria changed
  49. BATSE Observations of GRB000115
  50. GRB 991216: Updated BATSE parameters
  51. IR observations of GRB991216
  52. GRB 991216 Radio Observations
  53. GRB 991208 SAO-RAS Spectroscopy
  54. GRB 991208 Keck Spectroscopy
  55. GRB 991216: Extremely bright BATSE burst
  56. GRB991208, optical observations
  57. GRB991106: BeppoSAX/BATSE results
  58. BeppoSAX NFI Observation of GRB991106
  59. GRB 991105: BATSE Observations
  60. GRB 991106 Optical Observations
  61. GRB991014 BATSE Observations
  62. BATSE GRB trigger criteria
  63. GRB990806: BATSE Observations
  64. Late-time HST/STIS Observations of GRB 990510
  65. X-ray/GRB 1SAX J0835.9+5118, BATSE Observation
  66. GRB 990510: BATSE Observations
  67. GRB 990510 Optical Observations
  68. GRB 990506: BATSE Observations
  69. GRB 990506, Optical Observations
  70. GRB 990506 optical observations
  71. GRB 990506 optical observations
  72. GRB 990316 optical observations
  73. GRB990123, 15-GHz limits
  74. GRB 990123: BATSE Observations
  75. GRB 990123 Optical Follow-up
  76. GRB981220, Optical Observations
  77. GRB 981220:Optical Observations
  78. GRB 981226 - Infrared Observations
  79. GRB 980326/Host Galaxy
  80. GRB 980923 BATSE Observations
  81. GRB980703, Host galaxy multicolor photometry
  82. GRB 980703: BATSE Observations
  83. GRB 980613: BATSE Observations
  84. SGR1900+14
  85. SGR1900+14
  86. GRB980519 BATSE Observations
  87. BATSE on-board GRB trigger change
  88. GRB980425 BATSE observations
  89. GRB980329
  90. GRB 971214: KPNO Optical Observations
  91. GRB 970228: Keck/LRIS Optical Observations

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