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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: optical observation
  2. GRB 070125: WSRT Radio Detection
  3. GRB070129: MITSuME optical observation
  4. Radio detection of GRB 070125
  5. GRB061217: MAGIC telescope GeV observation
  6. GRB 070125: confirmation of pseudo-redshift
  7. GRB 070129, Swift-BAT refined analysis of a particularly long
  8. GRB 070129: Xinglong TNT optical Upper Limit
  9. GRB 070129: Swift-XRT Refined Analysis
  10. GRB 070129: VLT observations
  11. GRB 070125: An IR Point Source and an Apparent Host Galaxy
  12. GRB 070129: Swift detection of a burst
  13. GRB 070126: Swift/UVOT refined analysis
  14. GRB 070125: further AAVSO optical observations
  15. GRB 070125: MITSuME Okayama optical observation
  16. Konus-Wind observation of GRB 070125
  17. GRB 070125: AAVSO optical observations
  18. GRB 070125: optical observations
  19. GRB 070126: VLT observations
  20. GRB070126: Swift-XRT possible detection of an afterglow
  21. GRB 070125: PROMPT detections
  22. GRB 070124: Suzaku WAM observation of the prompt emissions
  23. GRB 070125: WSRT Radio Observations
  24. GRB 070125: UVOT Detection in Ultraviolet Filters
  25. GRB 070126, Swift-BAT refined analysis of a very faint burst
  26. GRB070125: Optical observation by Kanata
  27. GRB070124: Swift-XRT Observation
  28. Possible GRB 070126: Swift/UVOT Upper Limit
  29. GRB 070125: UVOT Observations of a Fading Optical Afterglow
  30. GRB 070125: Xinglong TNT optical observations
  31. GRB 070125: Continued P60 Observations
  32. GRB 070125: pseudo-z~1.5 from spectral parameters of the prompt emission
  33. GRB 070125: Keck/LRIS Spectroscopy -- Evidence for a very low redshift
  34. GRB 070125: Lick 3m Spectroscopy
  35. GRB070125: Swift-XRT Refined Analysis
  36. GRB 070125: SARA detection in R
  37. GRB 070125: P60 Optical Afterglow Candidate
  38. GRB 070126?: Swift detection of a possible burst
  39. GRB070125 redshift request
  40. RHESSI Spectrum of GRB070125
  41. IPN-BAT localization of GRB070125 (very long duration, intense)
  42. Konus-Wind observation of short hard GRB 070124
  43. IPN localization of GRB070124 (short duration, hard spectrum)
  44. GRB 070110: optical break
  45. Swift-BAT trigger 257213 is a Galactic Center transient
  46. GRB 070110: Continued Detection and Request for Ground Followup
  47. GRB 050904: Second Epoch of HST/NICMOS Observations
  48. GRB 070110: Ep,i - Eiso correlation
  49. GRB 070107: Suzaku WAM observation of the prompt emission
  50. GRB 070110: VLT R-band photometry
  51. GRB 070110 declared a "Burst of Interest" by Swift team
  52. Further Retractions of previous Swift-BAT triggers
  53. Swift-BAT Trigger 255685 is not a GRB
  54. Trigger 255685: Swift detection of a possible burst
  55. GRB 070110: VLT absorption redshift
  56. GRB 070110: UVOT Observations of a Candidate Afterglow
  57. GRB070110: Swift XRT Team refined analysis
  58. GRB 070110, Swift-BAT refined analysis
  59. GRB070107 Swift/UVOT Observations of a Fading Optical Afterglow
  60. GRB 070110: Swift detection of a burst with a possible optical afterglow
  61. IBAS Alert n. 4047: Not a GRB
  62. GRB070107: Swift/XRT refined analysis
  63. GRB 070107: Possible UVOT Afterglow
  64. GRB 070107, Swift-BAT refined analysis
  65. GRB 070107: Swift/XRT position
  66. GRB 070107: Swift detection of a burst
  67. VLA observation of GRB 061222B
  68. VLA detection of GRB 061222A
  69. GRB070103: APO SPIcam i' and z' limits
  70. GRB 061201: Nearby Galaxy Cluster Abell 995 is at z=0.0865
  71. GRB070103: KPNO 4m+FLAMINGOS J limit
  72. GRB 070103: Swift/UVOT Upper limits
  73. GRB070103: Swift XRT refined analysis
  74. GRB 070103, Swift-BAT refined analysis
  75. GRB 070103: NOT observations
  76. GRB 070103: TAROT Calern observatory optical observations
  77. GRB 070103: Swift detection of a burst
  78. Retractions of previous Swift-BAT triggers
  79. GRB061222a: optical observations
  80. erratum : SDSS Pre-burst Observations of GRB061126
  81. Konus-Wind observation of GRB 061222A
  82. GRB 061210: Swift/XRT Astrometry Correction
  83. GRB 050826: MDM Redshift
  84. GRB 061222B: TAROT La Silla observatory early optical observations
  85. GRB 061218: TAROT La Silla observatory early optical observations
  86. GRB 061222A: MITSuME Akeno optical upper limits
  87. GRB 061222A: Confirmation of Gemini Afterglow Candidate
  88. GRB 061222B: MITSuME Akeno optical upper limits
  89. GRB 061222A: Xinglong Optical Limit
  90. GRB 061222A: Gemini Afterglow Candidate
  91. GRB 061222B, Swift-BAT refined analysis
  92. GRB061222A Swift/UVOT: Upper Limits
  93. GRB 061222B: Swift/UVOT Upper limits
  94. GRB 061222B: Observation with the KANATA 1.5m telescope
  95. GRB061222B: Swift-XRT Refined Analysis
  96. GRB 061222A: Observation with the KANATA 1.5m telescope
  97. GRB 061222B: BOOTES-IR optical observations
  98. GRB 061222B: SARA upper limit
  99. GRB 061222A: Swift-XRT refined analysis
  100. GRB 061217: Magellan host galaxy redshift

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