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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: PROMPT detections
  2. GRB 070124: Suzaku WAM observation of the prompt emissions
  3. GRB 070125: WSRT Radio Observations
  4. GRB 070125: UVOT Detection in Ultraviolet Filters
  5. GRB 070126, Swift-BAT refined analysis of a very faint burst
  6. GRB070125: Optical observation by Kanata
  7. GRB070124: Swift-XRT Observation
  8. Possible GRB 070126: Swift/UVOT Upper Limit
  9. GRB 070125: UVOT Observations of a Fading Optical Afterglow
  10. GRB 070125: Xinglong TNT optical observations
  11. GRB 070125: Continued P60 Observations
  12. GRB 070125: pseudo-z~1.5 from spectral parameters of the prompt emission
  13. GRB 070125: Keck/LRIS Spectroscopy -- Evidence for a very low redshift
  14. GRB 070125: Lick 3m Spectroscopy
  15. GRB070125: Swift-XRT Refined Analysis
  16. GRB 070125: SARA detection in R
  17. GRB 070125: P60 Optical Afterglow Candidate
  18. GRB 070126?: Swift detection of a possible burst
  19. GRB070125 redshift request
  20. RHESSI Spectrum of GRB070125
  21. IPN-BAT localization of GRB070125 (very long duration, intense)
  22. Konus-Wind observation of short hard GRB 070124
  23. IPN localization of GRB070124 (short duration, hard spectrum)
  24. GRB 070110: optical break
  25. Swift-BAT trigger 257213 is a Galactic Center transient
  26. GRB 070110: Continued Detection and Request for Ground Followup
  27. GRB 050904: Second Epoch of HST/NICMOS Observations
  28. GRB 070110: Ep,i - Eiso correlation
  29. GRB 070107: Suzaku WAM observation of the prompt emission
  30. GRB 070110: VLT R-band photometry
  31. GRB 070110 declared a "Burst of Interest" by Swift team
  32. Further Retractions of previous Swift-BAT triggers
  33. Swift-BAT Trigger 255685 is not a GRB
  34. Trigger 255685: Swift detection of a possible burst
  35. GRB 070110: VLT absorption redshift
  36. GRB 070110: UVOT Observations of a Candidate Afterglow
  37. GRB070110: Swift XRT Team refined analysis
  38. GRB 070110, Swift-BAT refined analysis
  39. GRB070107 Swift/UVOT Observations of a Fading Optical Afterglow
  40. GRB 070110: Swift detection of a burst with a possible optical afterglow
  41. IBAS Alert n. 4047: Not a GRB
  42. GRB070107: Swift/XRT refined analysis
  43. GRB 070107: Possible UVOT Afterglow
  44. GRB 070107, Swift-BAT refined analysis
  45. GRB 070107: Swift/XRT position
  46. GRB 070107: Swift detection of a burst
  47. VLA observation of GRB 061222B
  48. VLA detection of GRB 061222A
  49. GRB070103: APO SPIcam i' and z' limits
  50. GRB 061201: Nearby Galaxy Cluster Abell 995 is at z=0.0865
  51. GRB070103: KPNO 4m+FLAMINGOS J limit
  52. GRB 070103: Swift/UVOT Upper limits
  53. GRB070103: Swift XRT refined analysis
  54. GRB 070103, Swift-BAT refined analysis
  55. GRB 070103: NOT observations
  56. GRB 070103: TAROT Calern observatory optical observations
  57. GRB 070103: Swift detection of a burst
  58. Retractions of previous Swift-BAT triggers
  59. GRB061222a: optical observations
  60. erratum : SDSS Pre-burst Observations of GRB061126
  61. Konus-Wind observation of GRB 061222A
  62. GRB 061210: Swift/XRT Astrometry Correction
  63. GRB 050826: MDM Redshift
  64. GRB 061222B: TAROT La Silla observatory early optical observations
  65. GRB 061218: TAROT La Silla observatory early optical observations
  66. GRB 061222A: MITSuME Akeno optical upper limits
  67. GRB 061222A: Confirmation of Gemini Afterglow Candidate
  68. GRB 061222B: MITSuME Akeno optical upper limits
  69. GRB 061222A: Xinglong Optical Limit
  70. GRB 061222A: Gemini Afterglow Candidate
  71. GRB 061222B, Swift-BAT refined analysis
  72. GRB061222A Swift/UVOT: Upper Limits
  73. GRB 061222B: Swift/UVOT Upper limits
  74. GRB 061222B: Observation with the KANATA 1.5m telescope
  75. GRB061222B: Swift-XRT Refined Analysis
  76. GRB 061222A: Observation with the KANATA 1.5m telescope
  77. GRB 061222B: BOOTES-IR optical observations
  78. GRB 061222B: SARA upper limit
  79. GRB 061222A: Swift-XRT refined analysis
  80. GRB 061217: Magellan host galaxy redshift
  81. GRB 061222A, Swift-BAT refined analysis
  82. GRB 061222B: REM NIR/optical observations
  83. GRB 061222b: Refined redshift
  84. GRB 061222b, SMARTS optical/IR afterglow observations
  85. GRB 061222B: TAROT La Silla observatory afterglow observation
  86. GRB 061222B: TAROT La Silla observatory optical observations
  87. GRB 061222b: Magellan redshift
  88. GRB 061222B: Swift detection of a burst
  89. GRB 061222b: optical afterglow
  90. GRB 061222A: Prompt ROTSE-III Optical Limits
  91. GRB 061222: Swift detection of a burst
  92. GRB 061217: Astrometry-Corrected XRT Position
  93. GRB 061201: Magellan redshift of nearby galaxy
  94. GRB 061217: Confirmation of host candidate
  95. GRB 061217: Object ib GCN 5948 is a star
  96. GRB 061217: Extended object in the revised XRT error circle
  97. GRB 061217, Candidate host galaxy
  98. GRB 061217 - Swift/XRT position correction
  99. GRB 061210: Possible Host Galaxy (S2-G2) Keck Spectrum
  100. GRB 061201: Correction to GCN 5944

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