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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. GRB 070125: confirmation of pseudo-redshift
  2. GRB 070129, Swift-BAT refined analysis of a particularly long
  3. GRB 070129: Xinglong TNT optical Upper Limit
  4. GRB 070129: Swift-XRT Refined Analysis
  5. GRB 070129: VLT observations
  6. GRB 070125: An IR Point Source and an Apparent Host Galaxy
  7. GRB 070129: Swift detection of a burst
  8. GRB 070126: Swift/UVOT refined analysis
  9. GRB 070125: further AAVSO optical observations
  10. GRB 070125: MITSuME Okayama optical observation
  11. Konus-Wind observation of GRB 070125
  12. GRB 070125: AAVSO optical observations
  13. GRB 070125: optical observations
  14. GRB 070126: VLT observations
  15. GRB070126: Swift-XRT possible detection of an afterglow
  16. GRB 070125: PROMPT detections
  17. GRB 070124: Suzaku WAM observation of the prompt emissions
  18. GRB 070125: WSRT Radio Observations
  19. GRB 070125: UVOT Detection in Ultraviolet Filters
  20. GRB 070126, Swift-BAT refined analysis of a very faint burst
  21. GRB070125: Optical observation by Kanata
  22. GRB070124: Swift-XRT Observation
  23. Possible GRB 070126: Swift/UVOT Upper Limit
  24. GRB 070125: UVOT Observations of a Fading Optical Afterglow
  25. GRB 070125: Xinglong TNT optical observations
  26. GRB 070125: Continued P60 Observations
  27. GRB 070125: pseudo-z~1.5 from spectral parameters of the prompt emission
  28. GRB 070125: Keck/LRIS Spectroscopy -- Evidence for a very low redshift
  29. GRB 070125: Lick 3m Spectroscopy
  30. GRB070125: Swift-XRT Refined Analysis
  31. GRB 070125: SARA detection in R
  32. GRB 070125: P60 Optical Afterglow Candidate
  33. GRB 070126?: Swift detection of a possible burst
  34. GRB070125 redshift request
  35. RHESSI Spectrum of GRB070125
  36. IPN-BAT localization of GRB070125 (very long duration, intense)
  37. Konus-Wind observation of short hard GRB 070124
  38. IPN localization of GRB070124 (short duration, hard spectrum)
  39. GRB 070110: optical break
  40. Swift-BAT trigger 257213 is a Galactic Center transient
  41. GRB 070110: Continued Detection and Request for Ground Followup
  42. GRB 050904: Second Epoch of HST/NICMOS Observations
  43. GRB 070110: Ep,i - Eiso correlation
  44. GRB 070107: Suzaku WAM observation of the prompt emission
  45. GRB 070110: VLT R-band photometry
  46. GRB 070110 declared a "Burst of Interest" by Swift team
  47. Further Retractions of previous Swift-BAT triggers
  48. Swift-BAT Trigger 255685 is not a GRB
  49. Trigger 255685: Swift detection of a possible burst
  50. GRB 070110: VLT absorption redshift
  51. GRB 070110: UVOT Observations of a Candidate Afterglow
  52. GRB070110: Swift XRT Team refined analysis
  53. GRB 070110, Swift-BAT refined analysis
  54. GRB070107 Swift/UVOT Observations of a Fading Optical Afterglow
  55. GRB 070110: Swift detection of a burst with a possible optical afterglow
  56. IBAS Alert n. 4047: Not a GRB
  57. GRB070107: Swift/XRT refined analysis
  58. GRB 070107: Possible UVOT Afterglow
  59. GRB 070107, Swift-BAT refined analysis
  60. GRB 070107: Swift/XRT position
  61. GRB 070107: Swift detection of a burst
  62. VLA observation of GRB 061222B
  63. VLA detection of GRB 061222A
  64. GRB070103: APO SPIcam i' and z' limits
  65. GRB 061201: Nearby Galaxy Cluster Abell 995 is at z=0.0865
  66. GRB070103: KPNO 4m+FLAMINGOS J limit
  67. GRB 070103: Swift/UVOT Upper limits
  68. GRB070103: Swift XRT refined analysis
  69. GRB 070103, Swift-BAT refined analysis
  70. GRB 070103: NOT observations
  71. GRB 070103: TAROT Calern observatory optical observations
  72. GRB 070103: Swift detection of a burst
  73. Retractions of previous Swift-BAT triggers
  74. GRB061222a: optical observations
  75. erratum : SDSS Pre-burst Observations of GRB061126
  76. Konus-Wind observation of GRB 061222A
  77. GRB 061210: Swift/XRT Astrometry Correction
  78. GRB 050826: MDM Redshift
  79. GRB 061222B: TAROT La Silla observatory early optical observations
  80. GRB 061218: TAROT La Silla observatory early optical observations
  81. GRB 061222A: MITSuME Akeno optical upper limits
  82. GRB 061222A: Confirmation of Gemini Afterglow Candidate
  83. GRB 061222B: MITSuME Akeno optical upper limits
  84. GRB 061222A: Xinglong Optical Limit
  85. GRB 061222A: Gemini Afterglow Candidate
  86. GRB 061222B, Swift-BAT refined analysis
  87. GRB061222A Swift/UVOT: Upper Limits
  88. GRB 061222B: Swift/UVOT Upper limits
  89. GRB 061222B: Observation with the KANATA 1.5m telescope
  90. GRB061222B: Swift-XRT Refined Analysis
  91. GRB 061222A: Observation with the KANATA 1.5m telescope
  92. GRB 061222B: BOOTES-IR optical observations
  93. GRB 061222B: SARA upper limit
  94. GRB 061222A: Swift-XRT refined analysis
  95. GRB 061217: Magellan host galaxy redshift
  96. GRB 061222A, Swift-BAT refined analysis
  97. GRB 061222B: REM NIR/optical observations
  98. GRB 061222b: Refined redshift
  99. GRB 061222b, SMARTS optical/IR afterglow observations
  100. GRB 061222B: TAROT La Silla observatory afterglow observation

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