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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"

36083 results found.

  1. GRB 060206: near-infrared observations (JK' imaging)
  2. GRB 060206: WSRT Radio Observations
  3. GRB 060203: Swift/UVOT upper limits
  4. GRB 060206: TTT Observations
  5. GRB 060206: More PROMPT Detections
  6. GRB 060121 : WIDGET Pre-trigger limit
  7. GRB 060206: Tenagra II Observations
  8. GRB 060206: PROMPT Detections
  9. Retraction of orphan GRB afterglow candidate
  10. GRB060204a: Swift XRT Source is not GRB Afterglow
  11. GRB 060206: optical observations at Asiago
  12. Orphan GRB Afterglow candidate
  13. GRB 060204b: pseudo-z from spectral parameters of the prompt emission
  14. GRB 060206: Subaru/FOCAS optical spectroscopy
  15. GRB 060206: IR Detection of the Afterglow
  16. GRB 060206: Lick 3m Spectroscopy
  17. GRB 060204A: ROSAT Pointing
  18. GRB 060206: Super-LOTIS observations
  19. GRB060204A: Swift/UVOT observations
  20. GRB 060206: Swift-BAT refined analysis
  21. GRB 060206 : Lulin optical observations
  22. GRB060206: SDSS Pre-Burst Observations
  23. GRB060206: Swift XRT Refined Analysis
  24. GRB060206: Liverpool Telescope observation
  25. GRB 060206: Spectroscopic Redshift
  26. GRB060206: P60 Optical Observations
  27. GRB 060206: KAIT observations
  28. GRB060206: Swift XRT Position
  29. GRB060206: SARA Detection
  30. GRB 060206: RAPTOR observations of afterglow candidate variability.
  31. GRB 060206: High redshift burst
  32. GRB060204a: Swift XRT Detection of an Afterglow Candidate
  33. GRB 060204C: XRT analysis of Swift J061223.0+701243.9
  34. BAT GRB 060204C is probably not a GRB
  35. GRB060204C: optical observation
  36. GRB 060204B: BVRi-band detections of optical afterglow
  37. GRB 060204A: Swift XRT upper limit
  38. GRB 060204A: FRAM optical observations
  39. GRB060204B: Swift/UVOT refined analysis
  40. GRB 060204C: optical observations
  41. Swift XRT Observation of GRB 060204C
  42. GRB 060204B: Swift-BAT refined analysis
  43. GRB 060204B: ART early limit
  44. GRB060204B: Swift XRT Team Refined Analysis
  45. GRB 060204C: OSN limits
  46. GRB 060204b: Keck/LRIS Afterglow Confirmation
  47. GRB 060204C: BOOTES-IR optical limits
  48. GRB 060204C: Liverpool Telescopes optical limit
  49. GRB 060204C: ROTSE-III Optical Limits
  50. GRB 060204C: Swift-BAT detection of a burst
  51. GRB 060124: Radio Observations
  52. GRB060204B: Faulkes OT candidate
  53. GRB 060204B: ART optical limit
  54. GRB 060204A: further INTEGRAL results
  55. GRB060204B - SDSS pre-burst observations
  56. GRB 060203: Swift-BAT refined analysis
  57. GRB 060204B: Swift detection of a burst
  58. GRB 060204: a long GRB detected by INTEGRAL
  59. GRB 060202: UKIRT/WFCAM K-band and KeckI/LRIS I-band Observation
  60. GRB 060203: RTT150 optical observations
  61. GRB060203: Swift XRT Team Refined Analysis
  62. Swift-BAT trigger is GRB 060203
  63. GRB 060203: IR Counterpart
  64. GRB060203: Observations with SARA
  65. GRB 060203: P60 Confirmation of Optical Afterglow
  66. Possible GRB 060203: candidate optical counterpart
  67. Possible GRB 060203: optical observations at Asiago
  68. GRB 060202: PROMPT Observations
  69. GRB 060202: GETS observation
  70. GRB 060202: Gemini-N J, H, K_s observations
  71. GRB 060202 : Kiso B and R band limit
  72. GRB 060202: Near-IR Observation with UKIRT/WFCAM
  73. GRB 060202: Optical Afterglow Candidate from Keck/LRIS
  74. GRB 060202: Refined analysis of the Swift-BAT burst
  75. GRB 060202: Swift/UVOT upper limits
  76. GRB 060202: Swift XRT Team Refined Analysis
  77. GRB 060202 : Lulin R and I band limit
  78. GRB060202: Faulkes North observation
  79. GRB 060202: Swift detection of a burst
  80. GRB 060121: Gemini Late-time Observations
  81. Erratum: SDSS pre-burst observations of GRB fields
  82. GRB 060130: PROMPT Observations
  83. GRB 060130: Swift/XRT observation
  84. GRB 051211A: MDM Observations
  85. GRB 060123: Gemini spectroscopy of the putative host galaxy
  86. GRB 060123: VLA Radio Observations
  87. GRB060130: Optical imaging
  88. GRB060130: REM infrared observations
  89. GRB 060130, SMARTS optical observations
  90. GRB 060130: FRAM optical observations
  91. GRB 060130: further INTEGRAL IBIS results
  92. GRB 060130: a long GRB detected with INTEGRAL
  93. Possible GRB 051221B: MDM Correction
  94. GRB050121: optical observation
  95. GRB050121b: optical observation
  96. GRB 060121: Confirmation of NIR Afterglow
  97. GRB060124: optical observation
  98. GRB060124: optical observations
  99. GRB 060123: Swift refined analysis of an unusual GRB
  100. GRB060124, BVRcIc field calibration

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