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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').
  1. GRB 070125: SARA detection in R
  2. GRB 070125: P60 Optical Afterglow Candidate
  3. GRB 070126?: Swift detection of a possible burst
  4. GRB070125 redshift request
  5. RHESSI Spectrum of GRB070125
  6. IPN-BAT localization of GRB070125 (very long duration, intense)
  7. Konus-Wind observation of short hard GRB 070124
  8. IPN localization of GRB070124 (short duration, hard spectrum)
  9. GRB 070110: optical break
  10. Swift-BAT trigger 257213 is a Galactic Center transient
  11. GRB 070110: Continued Detection and Request for Ground Followup
  12. GRB 050904: Second Epoch of HST/NICMOS Observations
  13. GRB 070110: Ep,i - Eiso correlation
  14. GRB 070107: Suzaku WAM observation of the prompt emission
  15. GRB 070110: VLT R-band photometry
  16. GRB 070110 declared a "Burst of Interest" by Swift team
  17. Further Retractions of previous Swift-BAT triggers
  18. Swift-BAT Trigger 255685 is not a GRB
  19. Trigger 255685: Swift detection of a possible burst
  20. GRB 070110: VLT absorption redshift
  21. GRB 070110: UVOT Observations of a Candidate Afterglow
  22. GRB070110: Swift XRT Team refined analysis
  23. GRB 070110, Swift-BAT refined analysis
  24. GRB070107 Swift/UVOT Observations of a Fading Optical Afterglow
  25. GRB 070110: Swift detection of a burst with a possible optical afterglow
  26. IBAS Alert n. 4047: Not a GRB
  27. GRB070107: Swift/XRT refined analysis
  28. GRB 070107: Possible UVOT Afterglow
  29. GRB 070107, Swift-BAT refined analysis
  30. GRB 070107: Swift/XRT position
  31. GRB 070107: Swift detection of a burst
  32. VLA observation of GRB 061222B
  33. VLA detection of GRB 061222A
  34. GRB070103: APO SPIcam i' and z' limits
  35. GRB 061201: Nearby Galaxy Cluster Abell 995 is at z=0.0865
  36. GRB070103: KPNO 4m+FLAMINGOS J limit
  37. GRB 070103: Swift/UVOT Upper limits
  38. GRB070103: Swift XRT refined analysis
  39. GRB 070103, Swift-BAT refined analysis
  40. GRB 070103: NOT observations
  41. GRB 070103: TAROT Calern observatory optical observations
  42. GRB 070103: Swift detection of a burst
  43. Retractions of previous Swift-BAT triggers
  44. GRB061222a: optical observations
  45. erratum : SDSS Pre-burst Observations of GRB061126
  46. Konus-Wind observation of GRB 061222A
  47. GRB 061210: Swift/XRT Astrometry Correction
  48. GRB 050826: MDM Redshift
  49. GRB 061222B: TAROT La Silla observatory early optical observations
  50. GRB 061218: TAROT La Silla observatory early optical observations
  51. GRB 061222A: MITSuME Akeno optical upper limits
  52. GRB 061222A: Confirmation of Gemini Afterglow Candidate
  53. GRB 061222B: MITSuME Akeno optical upper limits
  54. GRB 061222A: Xinglong Optical Limit
  55. GRB 061222A: Gemini Afterglow Candidate
  56. GRB 061222B, Swift-BAT refined analysis
  57. GRB061222A Swift/UVOT: Upper Limits
  58. GRB 061222B: Swift/UVOT Upper limits
  59. GRB 061222B: Observation with the KANATA 1.5m telescope
  60. GRB061222B: Swift-XRT Refined Analysis
  61. GRB 061222A: Observation with the KANATA 1.5m telescope
  62. GRB 061222B: BOOTES-IR optical observations
  63. GRB 061222B: SARA upper limit
  64. GRB 061222A: Swift-XRT refined analysis
  65. GRB 061217: Magellan host galaxy redshift
  66. GRB 061222A, Swift-BAT refined analysis
  67. GRB 061222B: REM NIR/optical observations
  68. GRB 061222b: Refined redshift
  69. GRB 061222b, SMARTS optical/IR afterglow observations
  70. GRB 061222B: TAROT La Silla observatory afterglow observation
  71. GRB 061222B: TAROT La Silla observatory optical observations
  72. GRB 061222b: Magellan redshift
  73. GRB 061222B: Swift detection of a burst
  74. GRB 061222b: optical afterglow
  75. GRB 061222A: Prompt ROTSE-III Optical Limits
  76. GRB 061222: Swift detection of a burst
  77. GRB 061217: Astrometry-Corrected XRT Position
  78. GRB 061201: Magellan redshift of nearby galaxy
  79. GRB 061217: Confirmation of host candidate
  80. GRB 061217: Object ib GCN 5948 is a star
  81. GRB 061217: Extended object in the revised XRT error circle
  82. GRB 061217, Candidate host galaxy
  83. GRB 061217 - Swift/XRT position correction
  84. GRB 061210: Possible Host Galaxy (S2-G2) Keck Spectrum
  85. GRB 061201: Correction to GCN 5944
  86. GRB 061201: Magellan Redshift of nearby Abell cluster
  87. GRB 061218: TAROT La Silla observatory optical observations
  88. GRB 061217: TAROT Calern observatory optical observations
  89. GRB 061218: TORTOREM optical upper limits
  90. GRB 061218, Swift-BAT refined analysis
  91. GRB061217: VLT NIR observations
  92. GRB 061218, SMARTS optical/IR observations
  93. GRB 061218: REM prompt observations
  94. Swift triggers (#251863) on a possible burst
  95. GRB 061217, SMARTS optical observations
  96. GRB061217: Swift/UVOT refined analysis.
  97. GRB 061217: optical observations at Calar Alto
  98. GRB061217 - Swift/XRT refined analysis
  99. GRB 061217, Further Swift-BAT refined analysis of the short hard burst
  100. GRB 061217, Swift-BAT refined analysis

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