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

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