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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"
  1. GRB070124: Swift-XRT Follow-up Observation
  2. GRB070126: Swift-XRT Observation
  3. GRB 070125: further AAVSO optical observations
  4. GRB 070129: Swift/UVOT Upper limits
  5. GRB 070129: dust-scattered X-ray halo detected by Swift/XRT
  6. GRB 070125: optical observation
  7. GRB 070125: WSRT Radio Detection
  8. GRB070129: MITSuME optical observation
  9. Radio detection of GRB 070125
  10. GRB061217: MAGIC telescope GeV observation
  11. GRB 070125: confirmation of pseudo-redshift
  12. GRB 070129, Swift-BAT refined analysis of a particularly long
  13. GRB 070129: Xinglong TNT optical Upper Limit
  14. GRB 070129: Swift-XRT Refined Analysis
  15. GRB 070129: VLT observations
  16. GRB 070125: An IR Point Source and an Apparent Host Galaxy
  17. GRB 070129: Swift detection of a burst
  18. GRB 070126: Swift/UVOT refined analysis
  19. GRB 070125: further AAVSO optical observations
  20. GRB 070125: MITSuME Okayama optical observation
  21. Konus-Wind observation of GRB 070125
  22. GRB 070125: AAVSO optical observations
  23. GRB 070125: optical observations
  24. GRB 070126: VLT observations
  25. GRB070126: Swift-XRT possible detection of an afterglow
  26. GRB 070125: PROMPT detections
  27. GRB 070124: Suzaku WAM observation of the prompt emissions
  28. GRB 070125: WSRT Radio Observations
  29. GRB 070125: UVOT Detection in Ultraviolet Filters
  30. GRB 070126, Swift-BAT refined analysis of a very faint burst
  31. GRB070125: Optical observation by Kanata
  32. GRB070124: Swift-XRT Observation
  33. Possible GRB 070126: Swift/UVOT Upper Limit
  34. GRB 070125: UVOT Observations of a Fading Optical Afterglow
  35. GRB 070125: Xinglong TNT optical observations
  36. GRB 070125: Continued P60 Observations
  37. GRB 070125: pseudo-z~1.5 from spectral parameters of the prompt emission
  38. GRB 070125: Keck/LRIS Spectroscopy -- Evidence for a very low redshift
  39. GRB 070125: Lick 3m Spectroscopy
  40. GRB070125: Swift-XRT Refined Analysis
  41. GRB 070125: SARA detection in R
  42. GRB 070125: P60 Optical Afterglow Candidate
  43. GRB 070126?: Swift detection of a possible burst
  44. GRB070125 redshift request
  45. RHESSI Spectrum of GRB070125
  46. IPN-BAT localization of GRB070125 (very long duration, intense)
  47. Konus-Wind observation of short hard GRB 070124
  48. IPN localization of GRB070124 (short duration, hard spectrum)
  49. GRB 070110: optical break
  50. Swift-BAT trigger 257213 is a Galactic Center transient
  51. GRB 070110: Continued Detection and Request for Ground Followup
  52. GRB 050904: Second Epoch of HST/NICMOS Observations
  53. GRB 070110: Ep,i - Eiso correlation
  54. GRB 070107: Suzaku WAM observation of the prompt emission
  55. GRB 070110: VLT R-band photometry
  56. GRB 070110 declared a "Burst of Interest" by Swift team
  57. Further Retractions of previous Swift-BAT triggers
  58. Swift-BAT Trigger 255685 is not a GRB
  59. Trigger 255685: Swift detection of a possible burst
  60. GRB 070110: VLT absorption redshift
  61. GRB 070110: UVOT Observations of a Candidate Afterglow
  62. GRB070110: Swift XRT Team refined analysis
  63. GRB 070110, Swift-BAT refined analysis
  64. GRB070107 Swift/UVOT Observations of a Fading Optical Afterglow
  65. GRB 070110: Swift detection of a burst with a possible optical afterglow
  66. IBAS Alert n. 4047: Not a GRB
  67. GRB070107: Swift/XRT refined analysis
  68. GRB 070107: Possible UVOT Afterglow
  69. GRB 070107, Swift-BAT refined analysis
  70. GRB 070107: Swift/XRT position
  71. GRB 070107: Swift detection of a burst
  72. VLA observation of GRB 061222B
  73. VLA detection of GRB 061222A
  74. GRB070103: APO SPIcam i' and z' limits
  75. GRB 061201: Nearby Galaxy Cluster Abell 995 is at z=0.0865
  76. GRB070103: KPNO 4m+FLAMINGOS J limit
  77. GRB 070103: Swift/UVOT Upper limits
  78. GRB070103: Swift XRT refined analysis
  79. GRB 070103, Swift-BAT refined analysis
  80. GRB 070103: NOT observations
  81. GRB 070103: TAROT Calern observatory optical observations
  82. GRB 070103: Swift detection of a burst
  83. Retractions of previous Swift-BAT triggers
  84. GRB061222a: optical observations
  85. erratum : SDSS Pre-burst Observations of GRB061126
  86. Konus-Wind observation of GRB 061222A
  87. GRB 061210: Swift/XRT Astrometry Correction
  88. GRB 050826: MDM Redshift
  89. GRB 061222B: TAROT La Silla observatory early optical observations
  90. GRB 061218: TAROT La Silla observatory early optical observations
  91. GRB 061222A: MITSuME Akeno optical upper limits
  92. GRB 061222A: Confirmation of Gemini Afterglow Candidate
  93. GRB 061222B: MITSuME Akeno optical upper limits
  94. GRB 061222A: Xinglong Optical Limit
  95. GRB 061222A: Gemini Afterglow Candidate
  96. GRB 061222B, Swift-BAT refined analysis
  97. GRB061222A Swift/UVOT: Upper Limits
  98. GRB 061222B: Swift/UVOT Upper limits
  99. GRB 061222B: Observation with the KANATA 1.5m telescope
  100. GRB061222B: Swift-XRT Refined Analysis

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