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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').
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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"

19593 results found.

  1. GRB 241115a: PRIME near-infrared upper limits
  2. GRB 241117A: Swift/BAT-GUANO localization skymap of a burst
  3. LIGO/Virgo/KAGRA S241116cq: Upper limits from Swift/BAT-GUANO
  4. GRB 241115B: Fermi GBM Observation
  5. GRB 241115B: Swift/BAT-GUANO localization skymap of a long burst
  6. GRB 241115C: Fermi GBM Observation
  7. GRB 241115A: Swift-XRT afterglow detection
  8. EP241115a/GRB 241115D: Optical upper limits with Kinder observations
  9. EP241115a/GRB 241115D: Swift/XRT follow-up observation
  10. EP241113a: Swift XRT weak detection
  11. GRB 241115A: Fermi GBM Observation
  12. GRB 241115A: LCOGT Optical Upper Limits
  13. GRB 241115C: Swift/BAT-GUANO localization skymap of a burst
  14. Swift GRB 241115A: Global MASTER-Net observations report
  15. GRB 241115A: Swift detection of a burst
  16. GRB 241113A: Swift-BAT refined analysis
  17. GRB 241113A: PRIME near-infrared upper limits
  18. GRB 241113A: J-band observations with WINTER
  19. GRB 241113B: Swift-XRT observations
  20. GRB 241113A: 1.6m Mephisto and 50cm array optical upper limits
  21. GRB 241113A: KAIT optical observations
  22. GRB 241113A: Swift-XRT refined Analysis
  23. GRB 241113A: Swift/UVOT Detection
  24. GRB 241113A: REM detection of the optical/NIR afterglow
  25. Konus-Wind detection of GRB 241107A (short/hard)
  26. GRB 241113B: Swift ToO observations
  27. GRB 241113A: LCO optical observations
  28. GRB 241113A: Enhanced Swift-XRT position
  29. GRB241113A: LCOGT (40-cm) optical counterpart detection
  30. GRB 241113A: MASTER010615.66-224018.2 optical counterpart detection
  31. GRB 241113A: Swift detection of a burst with an optical counterpart
  32. Swift GRB241113.33: Global MASTER-Net observations report
  33. GRB 241107A: GROWTH-India telescope optical upper limit
  34. GRB 241112B: Swift-XRT afterglow detection
  35. GRB 241107A: Swift/BAT candidate arcminute localization of a short burst
  36. GRB 241112B: Swift ToO observations
  37. GRB 241107A: INTEGRAL IBIS localization
  38. IPN triangulation of GRB 241107A (short/hard)
  39. GRB 241025A: VZLUSAT-2 detection
  40. GRB 241108A: Swift-XRT observations
  41. GRB 241108A: Swift ToO observations
  42. GRB 241030A: TESS observations
  43. GRB 241105A: EP-FXT follow-up observations
  44. GRB 241105A: SVOM/GRM observation
  45. GRB 241105a: PRIME near-infrared upper limits
  46. GRB 241105A: Swift/UVOT Detection
  47. GRB 241105A: Swift/BAT-GUANO refined analysis of short burst with extended emission
  48. GRB 241030A: optical afterglow detection from the INAF Asiago Observatory
  49. GRB 241105A: BOOTES-7 optical detection
  50. GRB 241105A: Fermi GBM Observation of a Short Burst with Extended Emission
  51. GRB 241105A: Swift-XRT afterglow detection
  52. GRB 241104A: Swift-XRT observations
  53. GRB 241105A: Swift ToO observations
  54. GRB 241105A: Swift/BAT-GUANO arcminute localization of a short burst
  55. GRB 241104A: Swift ToO observations
  56. GRB 241030A: GRBAlpha detection
  57. EP241103a: GIT optical upper limit
  58. EP241103a: GOTO optical upper limit
  59. EP241103a: Swift XRT detection and improved X-ray position
  60. GRB 241030A: Swift-UVOT observations of the optical prompt flare
  61. GRB 241030A: Rapid release of TESS data.
  62. Swift GRB 241101A: Global MASTER-Net observations report
  63. GRB 241101A: FRAM-ORM optical limit
  64. GRB 241101A: Swift-BAT refined analysis
  65. GRB 241030B: Swift-XRT refined Analysis
  66. GRB 241030A / EP241030a: GMG possible spectroscopic redshift at z ~ 1.4
  67. GRB 241101A: Swift detection of a burst
  68. GRB 241030B: Montarrenti Observatory optical upper limit
  69. GRB 241030A / EP241030a: FTW Optical and NIR observations of the optical counterpart
  70. GRB 241030A: Fermi GBM Observation
  71. GRB 241030B: LCOGT Optical Upper Limits
  72. GRB 241030B: Swift-BAT refined analysis
  73. GRB 241030A: Swift-BAT refined analysis
  74. GRB 241030B: Swift/UVOT Detection
  75. GRB 241029A: LCO optical detection
  76. Swift GRB241030.77: Global MASTER-Net observations report
  77. GRB 241030B: SVOM/GRM observation
  78. GRB 241030B : MITSuME Akeno optical upper limits
  79. GRB 241030A: COLIBRI Continuing Detection of the Afterglow
  80. GRB 241030B: COLIBRÍ Upper Limits on the Optical Counterpart
  81. GRB241030B: Fermi GBM Observation
  82. GRB 241030A: detection of the bright optical counterpart in ATLAS forced photometry
  83. GRB 241030B: Enhanced Swift-XRT position
  84. GRB 241030B: optical observations from the INAF Asiago Observatory
  85. EP241021a: Swift-UVOT detection
  86. GRB241030B: GRANDMA/TAROT Upper Limit
  87. GRB 241030A: Swift-XRT refined Analysis
  88. GRB 241030B: AKO Optical Afterglow Detection
  89. GRB 241030B: Nanshan/HMT optical afterglow detection
  90. GRB 241030B: SVOM/ECLAIRs detection of a burst
  91. GRB 241030B: Prompt enhanced Swift-XRT position
  92. Konus-Wind detection of GRB 241030A
  93. GRB 241030B: Swift detection of a burst
  94. GRB 241030A: Fermi-LAT detection
  95. GRB 241030A: AKO Optical Afterglow Detection
  96. Swift GRB 241030A: Global MASTER-Net observations report
  97. GRB 241030A: Swift/UVOT Detection
  98. EP 241021a: further Swift-XRT observations and X-ray counterpart detection
  99. GRB 241030A: SVOM/GRM observation
  100. GRB 241026A: Swift-BAT refined analysis

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