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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 110208A: Magellan confirmation of the optical afterglow
  2. Swift/UVOT observations of GRB110208a
  3. GRB 110208A: Potential afterglow from Magellan
  4. GRB 110208A: Magellan optical observations
  5. GRB 110206A: SMARTS optical/IR afterglow decay
  6. GRB 110205A: optical observations in Mondy observatory
  7. GRB 110205A : HCT optical observations
  8. GRB 110206A: SMARTS optical/IR afterglow candidate observations
  9. GRB 110207A: TAROT Calern observatory optical observations
  10. GRB 110205A - Continued PAIRITEL NIR Observations
  11. GRB 110205A: WSRT radio observation
  12. GRB110205A: CARMA 3mm Observations
  13. GRB 110207A: MASTER prompt and early optical observations
  14. GRB 110206A: TAROT La Silla observatory optical observations
  15. GRB 110205A: Lightbuckets Optical Observations
  16. GRB 110205A : Lulin optical observation
  17. GRB110205A: MITSuME Ishigakijima Optical Observation
  18. GRB110205A: MITSuME Okayama Optical Observation
  19. GRB110205A: SMA 1.3mm Observations
  20. GRB 110205A: Swift/UVOT Continuing Observations
  21. GRB 110205A: Lulin optical observations and temporal decay index
  22. GRB 110205A: Newcastle Observatory Optical Observations
  23. GRB 101225A is likely at z~0
  24. GRB 110205A: optical flare confirmation
  25. GRB 110205A: NOT redshift confirmation
  26. GRB 110205A: FAST Redshift
  27. GRB 110205A: GRAS005 optical observations
  28. GRB 110205A: PAIRITEL NIR Afterglow Detection
  29. GRB 110205A: TAROT Calern observatory detection of an optical flare
  30. GRB 110205A: ROTSE-III, Optical Counterpart is flaring to ~14 mag
  31. GRB 110205A: TAROT Calern observatory optical detection
  32. GRB 110205A: Swift detection of a burst with an optical candidate
  33. GRB110201A: MITSuME Okayama optical upper limits
  34. Swift/UVOT observations of GRB110201A
  35. GRB 110201A: MASTER optical observations
  36. GRB110128A: MITSuME Okayama optical upper limits
  37. GRB 101112A: Maidanak and CrAO optical observations
  38. GRB110128A: TNG NIR observations
  39. GRB 110128A: TAROT-Calern refined analysis
  40. GRB 110128A: Swift/UVOT observations
  41. GRB 110128A: VLT/X-shooter redshift
  42. GRB 110106B, radio observations
  43. GRB 110120A: MASTER optical observations
  44. GRB 101225A: CQUEAN optical observation
  45. GRB 110106A: CrAO optical observations
  46. GRB 110112A: optical upper limit
  47. GRB 110120A: MASTER optical observations
  48. GRB110119A: MITSuME Okayama optical upper limits
  49. GRB 110119A: Swift detection of a burst with an optical detection
  50. GRB 101219B: GROND detection of a SN signature
  51. Short GRB 110112B : early optical limit by "Pi of the Sky"
  52. The Christmas burst GRB 101225A - optical spectroscopy with GTC
  53. GRB 110112A: MITSuME Akeno and Okayama optical upper limits
  54. GRB 101225A: HST observations - no host detected
  55. GRB 101225A: Redshift retraction and results of additional photometric follow-up at the NOT
  56. GRB 110112A: Swift/UVOT upper limits
  57. GRB 110112A: MASTER optical observations
  58. GRB 110106B: MASTER optical observations
  59. GRB110112A: TNT optical afterglow candidate
  60. GRB 110106B: early optical and near-IR observations
  61. GRB 110107A: Swift/UVOT upper limits
  62. GRB 101219b. Possible radio afterglow detection.
  63. GRB 110106B: MASTER early optical observations
  64. GRB 110106A: ISAS-Kanazawa optical upper limit
  65. GRB 110106A: MITSuME Okayama optical upper limits
  66. GRB 110106A: Swift/UVOT Upper Limits
  67. GRB 110106A: TNG optical observations and candidate counterparts
  68. GRB 110106A: MASTER optical observations
  69. GRB 101225A: Host galaxy
  70. GRB 101219B: After 2 weeks still detected by Swift/UVOT
  71. GRB110102A: Swift/UVOT observations
  72. GRB110102A: MITSuME Okayama Optical Observation
  73. GRB 110102A: Swift detection of a burst with an optical detection
  74. GRB 101225A: optical break from NOT observation
  75. GRB 101225A: MMT spectroscopy
  76. GRB 101225A: P60 Observations
  77. GRB 101225: Optical follow-up of the Christmas burst
  78. Tentative redshift of GRB101225A (Christmas's burst) from Swift-XRT data
  79. Trigger 441015 / GRB 101225A: Further NOT optical observation
  80. Trigger 441015 / GRB 101225A: NOT optical afterglow candidate
  81. GRB 101225A (Swift trigger 441015): optical upper limit
  82. GRB 101224A: NOT optical observation
  83. GRB 101224A: Swift/UVOT Upper Limits
  84. GRB101224A: MITSuME Okayama optical upper limits
  85. GRB 101219B: Swift/UVOT refined analysis
  86. GRB 101219A: MITSuME Ishigakijima Optical upper limits
  87. GRB 101219B: GROND Detection of the Optical/NIR Afterglow
  88. GRB 101219A: IAC80 optical observations
  89. GRB 101219B: Swift detection of a burst with an optical afterglow
  90. GRB 101219A: Swift/UVOT Upper Limits
  91. GRB 101219A: GROND Upper limits
  92. GRB 101219A: Magellan NIR observations
  93. GRB 101219A - NOT observation - upper limit
  94. GRB 101219A: REM optical and NIR observations
  95. GRB 101219A: ROTSE-III Optical Limits
  96. XRF 101117A, RIMOTS optical upper limits
  97. GRB 101213A: Swift/UVOT Upper Limits
  98. GRB101204A GROND Detection of the Optical/NIR Afterglow
  99. GRB 101204A Afterglow Candidate, VATT Observations
  100. GRB 101201A: GROND Detection of the Optical/NIR Afterglow

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