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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"

37512 results found.

  1. GRB 060203: Swift-BAT refined analysis
  2. GRB 060204B: Swift detection of a burst
  3. GRB 060204: a long GRB detected by INTEGRAL
  4. GRB 060202: UKIRT/WFCAM K-band and KeckI/LRIS I-band Observation
  5. GRB 060203: RTT150 optical observations
  6. GRB060203: Swift XRT Team Refined Analysis
  7. Swift-BAT trigger is GRB 060203
  8. GRB 060203: IR Counterpart
  9. GRB060203: Observations with SARA
  10. GRB 060203: P60 Confirmation of Optical Afterglow
  11. Possible GRB 060203: candidate optical counterpart
  12. Possible GRB 060203: optical observations at Asiago
  13. GRB 060202: PROMPT Observations
  14. GRB 060202: GETS observation
  15. GRB 060202: Gemini-N J, H, K_s observations
  16. GRB 060202 : Kiso B and R band limit
  17. GRB 060202: Near-IR Observation with UKIRT/WFCAM
  18. GRB 060202: Optical Afterglow Candidate from Keck/LRIS
  19. GRB 060202: Refined analysis of the Swift-BAT burst
  20. GRB 060202: Swift/UVOT upper limits
  21. GRB 060202: Swift XRT Team Refined Analysis
  22. GRB 060202 : Lulin R and I band limit
  23. GRB060202: Faulkes North observation
  24. GRB 060202: Swift detection of a burst
  25. GRB 060121: Gemini Late-time Observations
  26. Erratum: SDSS pre-burst observations of GRB fields
  27. GRB 060130: PROMPT Observations
  28. GRB 060130: Swift/XRT observation
  29. GRB 051211A: MDM Observations
  30. GRB 060123: Gemini spectroscopy of the putative host galaxy
  31. GRB 060123: VLA Radio Observations
  32. GRB060130: Optical imaging
  33. GRB060130: REM infrared observations
  34. GRB 060130, SMARTS optical observations
  35. GRB 060130: FRAM optical observations
  36. GRB 060130: further INTEGRAL IBIS results
  37. GRB 060130: a long GRB detected with INTEGRAL
  38. Possible GRB 051221B: MDM Correction
  39. GRB050121: optical observation
  40. GRB050121b: optical observation
  41. GRB 060121: Confirmation of NIR Afterglow
  42. GRB060124: optical observation
  43. GRB060124: optical observations
  44. GRB 060123: Swift refined analysis of an unusual GRB
  45. GRB060124, BVRcIc field calibration
  46. GRB060105: refined analysis of the Suzaku observation
  47. GRB060124 optical observations
  48. GRB 060121: Probable Detection of NIR Afterglow
  49. GRB060124: optical observation
  50. GRB 060116 HST observations
  51. GRB 060124: HETE detection and spectrum of the main peak
  52. Refined XRT Position for GRB 060123
  53. Konus-Wind observation of GRB 060124
  54. GRB060124: detailed XRT analysis
  55. GRB 060124 Optical Observations
  56. GRB 060124: ART optical limits during the burst
  57. GRB060123: Optical and IR Imaging
  58. GRB 060123: P200 Observations
  59. GRB 060124: Keck optical spectrum
  60. GRB 060124: Keck Absorption Redshift
  61. GRB 060124: MDM Optical Spectrum
  62. GRB 060124: XRT refined analysis
  63. GRB 060124: R band Observations
  64. GRB 060124 : Optical observation at Xinglong and Kiso
  65. GRB060124: optical observations at Asiago
  66. GRB 060124: Extremely long burst, Swift-BAT refined analysis
  67. GRB060123: SDSS pre-burst observations
  68. GRB 060123: Swift detection of a very long, faint burst
  69. GRB 060116: Further analysis of VLT photometry and optical spectroscopy
  70. GRB 060121: OHP optical limits
  71. GRB 060124: TAROT optical limits
  72. GRB 060124: Swift/UVOT Observation
  73. GRB 060124: Confirmation of the Afterglow
  74. GRB 060124: XRT position
  75. GRB 060124: Optical Afterglow Candidate from Tautenburg
  76. GRB 050124 : Kiso Optical limit
  77. GRB 060124: Optical Observations at Tautenburg
  78. GRB 060117: Suzaku WAM observation of the prompt emission
  79. GRB060124:MASTER optical observation
  80. GRB 060111B: Suzaku WAM observation of the prompt emission
  81. GRB 060124: Swift-BAT detection of a burst
  82. GRB 060116: Radio Detection
  83. GRB 060116: MARGE optical observations
  84. GRB 060121: Swift/UVOT upper limits
  85. GRB 060121: Liverpool Telescopes optical limits
  86. GRB 060121: Swift XRT refined analysis
  87. Konus-Wind observation of GRB 060121
  88. GRB 060121: I-band Limits
  89. GRB 060121: Confirmation of Afterglow
  90. GRB 060121: candidate optical counterpart
  91. GRB 060121: Swift XRT refined position
  92. GRB060121: SARA Observations
  93. GRB 060121: optical observations
  94. GRB 060121: Infrared Observations
  95. GRB 060121: optical observations
  96. GRB 060121: Optical imaging
  97. GRB060121 - SDSS pre-burst observations
  98. GRB 060121: A short-hard GRB in a cluster?
  99. GRB 060121 (=H4010): Results of preliminary spectral analysis
  100. GRB 060121: A bright short/hard GRB localized by HETE-2 SXC

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