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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"

16159 results found.

  1. GRB 111123A: optical upper limit in CrAO
  2. GRB 111201A: Swift/UVOT Upper Limits
  3. GRB 111129A, GROND afterglow observations
  4. GRB 111129A: Swift detection of a burst with an optical counterpart
  5. GRB 111123A: Swift/UVOT Upper Limits
  6. GRB 111123A - NOT optical observations
  7. GRB 111123A, GROND observations
  8. GRB 111123A: MITSuME Okayama Optical upper limits
  9. GRB 111123A: GMG optical observation
  10. GRB 111117A: Refined Chandra Astrometry
  11. GRB 111121A: Swift/UVOT Upper Limits
  12. GRB 111117A: Chandra detection of the afterglow
  13. GRB 111117A: optical upper limit in CrAO
  14. GRB 111117A: further NOT observations
  15. GRB 111117A: Swift/UVOT Upper Limits
  16. GRB 111117A: NOT observations
  17. GRB 111117A: Chandra ToO observation scheduled
  18. GRB 111103B: optical upper limit of CrAO
  19. GRB 111103B: optical upper limit of Mt. Terskol observatory
  20. Continued Skynet observations of GRB111107A
  21. GRB 111107A: VLT/X-shooter spectroscopy
  22. GRB 111107A: Gemini-South Redshift
  23. Skynet observations of GRB 111107A
  24. GRB 111107A: Swift detection of a burst with an optical counterpart
  25. GRB 111103B: MITSuME Akeno Optical upper limits
  26. GRB111103B Swift/UVOT Upper Limits
  27. GRB 111103B: optical observations from TAU, Ka-Dar
  28. Trigger 506913: MASTER detection of Swift J1922.7-1716 optical counterpart
  29. Trigger 506913: Swift detection of Swift J1922.7-1716 and its optical counterpart
  30. GRB 111022B: MASTER OT observations
  31. GRB 111103B: optical observations
  32. GRB 111103B: Swift detection of a strong burst from a GRB or Galactic source
  33. GRB 111029A: RAPTOR Limits During the Gamma-ray Emitting Interval
  34. GRB 111029A: SAO RAS optical limits
  35. GRB111029A: MITSuME Ishigakijima Optical Upper Limits
  36. GRB 111029A: TNT optical upper limit, Correction to GCN 12503
  37. GRB 111029A: Swift/UVOT Upper Limits
  38. GRB 111029A: KAIT optical limits
  39. GRB 111029A: TNT optical upper limit
  40. GRB 111029A: optical upper limit
  41. GRB 111029A: ROTSE-III Optical Limits
  42. GRB 111022B: 10.4m GTC z'-band observations
  43. GRB111022B: D50 optical limit
  44. GRB 111022B: BTA Optical Observations
  45. GRB 111022A: MITSuME Akeno Optical upper limits
  46. GRB 111022A: Swift/UVOT Upper Limits
  47. GRB 111016A: optical upper limit
  48. GRB 111022B: Gemini infrared observations
  49. GRB 111022B: MITSuME Akeno Optical upper limits
  50. GRB 111022B: NOT observations
  51. GRB 111022B: MASTER-Net early limit
  52. GRB 111022A: MASTER-Net early limit
  53. GRB 111020A: Gemini-South additional observations and limit on an optical afterglow
  54. GRB 111020A: Swift/UVOT Upper Limits
  55. GRB 111020A: BOOTES-3 Optical Upper Limit.
  56. GRB 111018A: Swift/UVOT Upper Limits
  57. GRB 110918A: Optical light curve for days 1.4 to 16.3
  58. GRB111016A: D50 optical limit
  59. GRB 111016A: Gemini Detection of the NIR Counterpart
  60. GRB 111016A: Swift/UVOT Detection of a Source
  61. GRB 111016A: MITSuME Akeno Optical upper limits
  62. GRB 110921A: optical observations
  63. EVLA 22 GHz Detection of GRB 111008A
  64. GRB 111008A: Swift/UVOT Upper Limits
  65. GRB 111008A: VLT/X-shooter spectroscopy
  66. GRB 111008A: Gemini spectroscopic redshift
  67. GRB 111008A: NOT optical observation
  68. GRB 111008A: Gemini optical counterpart
  69. GRB 111005A: ATCA 18 GHz detection
  70. GRB 111005A: VLT optical observations
  71. GRB 110905A / MAXI J1836-194: optical monitoring
  72. GRB 110921A: MITSuME-Akeno Optical photometry
  73. Skynet observations of GRB 110928A
  74. GRB 110928A: RAPTOR Limits During Gamma-ray Emitting Interval
  75. GRB 110928A: Swift/UVOT Upper Limits
  76. GRB 110825A: GROND Observations
  77. GRB 110928A: ROTSE-III Optical Limits
  78. GRB 110921A: Swift/UVOT Observations
  79. GRB110918A: Lick Observations
  80. GRB 110921A: NOT observations
  81. GRB 110921A: TNT astrometry
  82. GRB 110918A: Liverpool Telescope optical observations
  83. GRB 110921A: optical observations in Mt. Terskol and Maidanak observatories
  84. GRB 110921A: MITSuME Akeno Optical Observation
  85. GRB 110921A : TNT optical counterpart candidate
  86. GRB 110921A: MASTER-Net early limit
  87. GRB 110915B : X-ray afterglow confirmation
  88. GRB 110918A: Swift/UVOT Detection of the Optical Counterpart
  89. GRB 110918A optical observation
  90. GRB 110918A: Gemini-N redshift
  91. GRB 110918A: Afterglow Confirmation from PTF
  92. GRB 110918A: GROND detection of the afterglow candidate
  93. GRB 110918A: INT optical detection of Swift candidate afterglow
  94. GRB110918A: BOOTES-1 optical limit
  95. GRB 110915B: GROND Observations of the Optical/NIR Afterglow Candidate
  96. GRB 110915A: Swift/UVOT Upper Limits
  97. GRB 110915B: Swift/UVOT Upper Limits
  98. GRB 110915A: Deep Gemini-South i/z-band imaging
  99. GRB 110915A: MITSuME Okayama and Ishigakijima Optical upper limits
  100. GRB 110915A: NOT observations

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