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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"

36039 results found.

  1. GRB060206: SARA Detection
  2. GRB 060206: RAPTOR observations of afterglow candidate variability.
  3. GRB 060206: High redshift burst
  4. GRB060204a: Swift XRT Detection of an Afterglow Candidate
  5. GRB 060204C: XRT analysis of Swift J061223.0+701243.9
  6. BAT GRB 060204C is probably not a GRB
  7. GRB060204C: optical observation
  8. GRB 060204B: BVRi-band detections of optical afterglow
  9. GRB 060204A: Swift XRT upper limit
  10. GRB 060204A: FRAM optical observations
  11. GRB060204B: Swift/UVOT refined analysis
  12. GRB 060204C: optical observations
  13. Swift XRT Observation of GRB 060204C
  14. GRB 060204B: Swift-BAT refined analysis
  15. GRB 060204B: ART early limit
  16. GRB060204B: Swift XRT Team Refined Analysis
  17. GRB 060204C: OSN limits
  18. GRB 060204b: Keck/LRIS Afterglow Confirmation
  19. GRB 060204C: BOOTES-IR optical limits
  20. GRB 060204C: Liverpool Telescopes optical limit
  21. GRB 060204C: ROTSE-III Optical Limits
  22. GRB 060204C: Swift-BAT detection of a burst
  23. GRB 060124: Radio Observations
  24. GRB060204B: Faulkes OT candidate
  25. GRB 060204B: ART optical limit
  26. GRB 060204A: further INTEGRAL results
  27. GRB060204B - SDSS pre-burst observations
  28. GRB 060203: Swift-BAT refined analysis
  29. GRB 060204B: Swift detection of a burst
  30. GRB 060204: a long GRB detected by INTEGRAL
  31. GRB 060202: UKIRT/WFCAM K-band and KeckI/LRIS I-band Observation
  32. GRB 060203: RTT150 optical observations
  33. GRB060203: Swift XRT Team Refined Analysis
  34. Swift-BAT trigger is GRB 060203
  35. GRB 060203: IR Counterpart
  36. GRB060203: Observations with SARA
  37. GRB 060203: P60 Confirmation of Optical Afterglow
  38. Possible GRB 060203: candidate optical counterpart
  39. Possible GRB 060203: optical observations at Asiago
  40. GRB 060202: PROMPT Observations
  41. GRB 060202: GETS observation
  42. GRB 060202: Gemini-N J, H, K_s observations
  43. GRB 060202 : Kiso B and R band limit
  44. GRB 060202: Near-IR Observation with UKIRT/WFCAM
  45. GRB 060202: Optical Afterglow Candidate from Keck/LRIS
  46. GRB 060202: Refined analysis of the Swift-BAT burst
  47. GRB 060202: Swift/UVOT upper limits
  48. GRB 060202: Swift XRT Team Refined Analysis
  49. GRB 060202 : Lulin R and I band limit
  50. GRB060202: Faulkes North observation
  51. GRB 060202: Swift detection of a burst
  52. GRB 060121: Gemini Late-time Observations
  53. Erratum: SDSS pre-burst observations of GRB fields
  54. GRB 060130: PROMPT Observations
  55. GRB 060130: Swift/XRT observation
  56. GRB 051211A: MDM Observations
  57. GRB 060123: Gemini spectroscopy of the putative host galaxy
  58. GRB 060123: VLA Radio Observations
  59. GRB060130: Optical imaging
  60. GRB060130: REM infrared observations
  61. GRB 060130, SMARTS optical observations
  62. GRB 060130: FRAM optical observations
  63. GRB 060130: further INTEGRAL IBIS results
  64. GRB 060130: a long GRB detected with INTEGRAL
  65. Possible GRB 051221B: MDM Correction
  66. GRB050121: optical observation
  67. GRB050121b: optical observation
  68. GRB 060121: Confirmation of NIR Afterglow
  69. GRB060124: optical observation
  70. GRB060124: optical observations
  71. GRB 060123: Swift refined analysis of an unusual GRB
  72. GRB060124, BVRcIc field calibration
  73. GRB060105: refined analysis of the Suzaku observation
  74. GRB060124 optical observations
  75. GRB 060121: Probable Detection of NIR Afterglow
  76. GRB060124: optical observation
  77. GRB 060116 HST observations
  78. GRB 060124: HETE detection and spectrum of the main peak
  79. Refined XRT Position for GRB 060123
  80. Konus-Wind observation of GRB 060124
  81. GRB060124: detailed XRT analysis
  82. GRB 060124 Optical Observations
  83. GRB 060124: ART optical limits during the burst
  84. GRB060123: Optical and IR Imaging
  85. GRB 060123: P200 Observations
  86. GRB 060124: Keck optical spectrum
  87. GRB 060124: Keck Absorption Redshift
  88. GRB 060124: MDM Optical Spectrum
  89. GRB 060124: XRT refined analysis
  90. GRB 060124: R band Observations
  91. GRB 060124 : Optical observation at Xinglong and Kiso
  92. GRB060124: optical observations at Asiago
  93. GRB 060124: Extremely long burst, Swift-BAT refined analysis
  94. GRB060123: SDSS pre-burst observations
  95. GRB 060123: Swift detection of a very long, faint burst
  96. GRB 060116: Further analysis of VLT photometry and optical spectroscopy
  97. GRB 060121: OHP optical limits
  98. GRB 060124: TAROT optical limits
  99. GRB 060124: Swift/UVOT Observation
  100. GRB 060124: Confirmation of the Afterglow

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