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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"

15986 results found.

  1. GRB 070125, deep late-time optical observation
  2. GRB 070227: optical observations
  3. GRB 070223: Optical Observations
  4. GRB 070227: optical observations
  5. GRB 070227: TAROT La Silla observatory optical observations
  6. GRB 920925C: optical afterglow candidate
  7. GRB 070224: Optical afterglow confirmation
  8. GRB070224: Swift-XRT Astrometrically Corrected Position
  9. GRB 070224: optical afterglow candidate
  10. GRB 070223: Optical observations
  11. GRB 070223: Optical-IR observation with KANATA
  12. GRB 070223: Swift-XRT Refined Analysis
  13. GRB 070223: MDM Observations
  14. GRB 070220: MITSuME Okayama Optical Observation
  15. GRB 070220: ART-3 Optical and NIR limits
  16. GRB 070220: Observation with the KANATA 1.5m telescope
  17. GRB 070220 : Faulkes Telescope North optical limit
  18. GRB 070219: optical TNG observations
  19. GRB 070219: ROTSE-III Optical Limits
  20. GRB 070129: MDM I-band Detection
  21. GRB 070125: Break in Optical Decay
  22. GRB070208: optical observations
  23. GRB 070208: MARGE Optical Observations
  24. GRB 070208: RAPTOR detection of early afterglow onset
  25. GRB070208: Absorption and emission redshift from Gemini
  26. GRB 070208: MDM Optical Decay
  27. GRB 070208: Early IR detection and afterglow astrometry
  28. GRB 070208: ROTSE-III Optical Limits
  29. GRB 070208: MDM Observations
  30. GRB 070125 detection with CARMA
  31. GRB 070125: Redshift z>~1.54 from Gemini Afterglow Spectrum
  32. GRB 070125: further AAVSO optical observations
  33. GRB 070125: optical observation
  34. GRB 070125: WSRT Radio Detection
  35. GRB070129: MITSuME optical observation
  36. GRB 070129: Xinglong TNT optical Upper Limit
  37. GRB 070125: further AAVSO optical observations
  38. GRB 070125: MITSuME Okayama optical observation
  39. GRB 070125: AAVSO optical observations
  40. GRB 070125: optical observations
  41. GRB 070125: WSRT Radio Observations
  42. GRB070125: Optical observation by Kanata
  43. Possible GRB 070126: Swift/UVOT Upper Limit
  44. GRB 070125: UVOT Observations of a Fading Optical Afterglow
  45. GRB 070125: Xinglong TNT optical observations
  46. GRB 070125: Continued P60 Observations
  47. GRB070125: Swift-XRT Refined Analysis
  48. GRB 070125: P60 Optical Afterglow Candidate
  49. GRB 070110: optical break
  50. GRB 070110: Continued Detection and Request for Ground Followup
  51. GRB 070110 declared a "Burst of Interest" by Swift team
  52. GRB 070110: VLT absorption redshift
  53. GRB 070110: UVOT Observations of a Candidate Afterglow
  54. GRB070107 Swift/UVOT Observations of a Fading Optical Afterglow
  55. GRB 070110: Swift detection of a burst with a possible optical afterglow
  56. GRB070107: Swift/XRT refined analysis
  57. GRB 061201: Nearby Galaxy Cluster Abell 995 is at z=0.0865
  58. GRB 070103: TAROT Calern observatory optical observations
  59. GRB061222a: optical observations
  60. GRB 061210: Swift/XRT Astrometry Correction
  61. GRB 050826: MDM Redshift
  62. GRB 061222B: TAROT La Silla observatory early optical observations
  63. GRB 061218: TAROT La Silla observatory early optical observations
  64. GRB 061222A: MITSuME Akeno optical upper limits
  65. GRB 061222B: MITSuME Akeno optical upper limits
  66. GRB 061222A: Xinglong Optical Limit
  67. GRB061222A Swift/UVOT: Upper Limits
  68. GRB 061222B: Observation with the KANATA 1.5m telescope
  69. GRB061222B: Swift-XRT Refined Analysis
  70. GRB 061222A: Observation with the KANATA 1.5m telescope
  71. GRB 061222B: BOOTES-IR optical observations
  72. GRB 061222B: REM NIR/optical observations
  73. GRB 061222b, SMARTS optical/IR afterglow observations
  74. GRB 061222B: TAROT La Silla observatory optical observations
  75. GRB 061222b: optical afterglow
  76. GRB 061222A: Prompt ROTSE-III Optical Limits
  77. GRB 061217: Astrometry-Corrected XRT Position
  78. GRB 061201: Magellan redshift of nearby galaxy
  79. GRB 061217, Candidate host galaxy
  80. GRB 061218: TAROT La Silla observatory optical observations
  81. GRB 061217: TAROT Calern observatory optical observations
  82. GRB 061218: TORTOREM optical upper limits
  83. GRB 061218, SMARTS optical/IR observations
  84. GRB 061218: REM prompt observations
  85. GRB 061217, SMARTS optical observations
  86. GRB061217: Swift/UVOT refined analysis.
  87. GRB 061217: optical observations at Calar Alto
  88. GRB 061217: REM prompt observations
  89. GRB 061217: ROTSE-III Optical Limits
  90. GRB 061210: MDM Follow-up Observation
  91. GRB061210: Swift/UVOT observations
  92. GRB 061210: Optical sources near XRT positions
  93. GRB 061210 : Faulkes North Telescope optical limit
  94. GRB 061214(?): ROTSE-III Optical Limits
  95. GRB 061213: MASTER-VWF-Kislovodsk optical candidate
  96. GRB061201, VLT optical decay: correction
  97. Optical Afterglow observations of GRB 061126
  98. GRB061126: optical observations
  99. GRB 060926: MASTER: discovery of the optical flare
  100. GRB 061201: UVOT Observations of a Fading Optical Afterglow

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