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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"

35428 results found.

  1. GRB 241115A: Swift-XRT afterglow detection
  2. EP241115a/GRB 241115D: Optical upper limits with Kinder observations
  3. GRB 241115A: Mephisto upper limits
  4. GRB 241113B: Mephisto upper limits
  5. EP241115a/GRB 241115D: Swift/XRT follow-up observation
  6. GRB 241115D / EP 241115a: SVOM/GRM observation
  7. GRB 241115A: Fermi GBM Observation
  8. GRB 241115A: LCOGT Optical Upper Limits
  9. GRB 241115C: Swift/BAT-GUANO localization skymap of a burst
  10. Fermi GRB 241115B: Global MASTER-Net observations report
  11. GRB 241115B: Fermi GBM Final Real-time Localization
  12. EP241113a: No Detection in Fermi-GBM Observations
  13. Swift GRB 241115A: Global MASTER-Net observations report
  14. Fermi GRB 241115A: Global MASTER-Net observations report
  15. GRB 241115A: Swift detection of a burst
  16. GRB 241115A: Fermi GBM Final Real-time Localization
  17. GRB 241113B: KAIT Optical Afterglow Candidate
  18. LIGO/Virgo/KAGRA S241114bi: Upper limits from Fermi-GBM Observations
  19. GRB 241113A: Swift-BAT refined analysis
  20. GRB 241113A: PRIME near-infrared upper limits
  21. Fermi GRB 241114A: Global MASTER-Net observations report
  22. GRB 241114A: Fermi GBM Final Real-time Localization
  23. GRB 241113B: J-band upper limit from WINTER
  24. GRB 241113A: J-band observations with WINTER
  25. GRB 241030A: LCO optical observation
  26. GRB 241113B: Swift-XRT observations
  27. IceCube-241113A: Upper limits from a search for additional neutrino events in IceCube
  28. GRB 241113A: 1.6m Mephisto and 50cm array optical upper limits
  29. GRB 241113A: KAIT optical observations
  30. EP241113b/GRB 241113B: EP detection of GRB 241113B
  31. GRB 241113B: SVOM/GRM observation
  32. GRB 241113A: Swift-XRT refined Analysis
  33. GRB 241113A: Swift/UVOT Detection
  34. GRB 241113A: REM detection of the optical/NIR afterglow
  35. Konus-Wind detection of GRB 241107A (short/hard)
  36. Fermi Gamma-ray Burst Monitor trigger 753166198/241113201 is not a GRB
  37. GRB 241113B: Swift ToO observations
  38. GRB 241113A: LCO optical observations
  39. GRB 241112B: GMG Optical Upper Limit
  40. GRB 241113A: Enhanced Swift-XRT position
  41. GRB241113A: LCOGT (40-cm) optical counterpart detection
  42. GRB 241113B : detection of a long GRB by SVOM/ECLAIRs
  43. GRB 241113A: MASTER010615.66-224018.2 optical counterpart detection
  44. GRB 241113A: Swift detection of a burst with an optical counterpart
  45. GRB 241105A: ATCA Radio Upper Limits
  46. GRB 241112B: AbAO optical upper limit
  47. GRB 241107A: GROWTH-India telescope optical upper limit
  48. Fermi GRB 241112A: Global MASTER-Net observations report
  49. Fermi-GBM Sub-Threshold Detection of GRB 241112B
  50. GRB 241112B: Optical afterglow detection confirmation in revisiting the Mephisto data
  51. GRB 241112B: Swift-XRT afterglow detection
  52. GRB 241112B: LCO optical detection of the SVOM/VT candidate
  53. GRB 241112B: SVOM/GRM observation
  54. GRB 241112B: SVOM/VT afterglow detection
  55. Fermi Gamma-ray Burst Monitor trigger 752995908/241111230 (GRB 241111A) is not a GRB
  56. GRB 241107A: Swift/BAT candidate arcminute localization of a short burst
  57. GRB 241112B: Mephisto optical upper limits
  58. GRB 241112B: GOTO optical upper limits
  59. GRB 241112B: Swift ToO observations
  60. GRB 241112B : detection of a long GRB by SVOM/ECLAIRs
  61. GRB 241107A: INTEGRAL IBIS localization
  62. GRB 241112A: Fermi GBM Final Real-time Localization
  63. GRB 241105A: VLT/FORS2 refined spectroscopic redshift z = 2.681
  64. IPN triangulation of GRB 241107A (short/hard)
  65. GRB 241107A: INTEGRAL/IBIS/PICsIT detection of a short burst
  66. GRB 241025C: VZLUSAT-2 detection
  67. GRB 241025A: VZLUSAT-2 detection
  68. GRB 241018A: cubesat Avion detection
  69. GRB 241111A: Fermi GBM Final Real-time Localization
  70. GRB 241030B: TESS detection of optical counterpart
  71. EP241109a: KAIT photometry and 3 m Shane spectroscopy from Lick observatory
  72. EP241107a: AbAO optical upper limit
  73. LIGO/Virgo/KAGRA S241109bn: Upper limits from Fermi-GBM Observations
  74. GRB 241108A: Further COLIBRÍ Upper Limits on the Optical Counterpart
  75. EP241109a: confirmation of a stellar flare by BOOTES-7
  76. GRB 241108A: Swift-XRT observations
  77. EP241107A: MASTER optical observations of xray transient
  78. EP241107a: KAIT optical observations
  79. GRB 241108A: Swift ToO observations
  80. GRB 241030A: TESS observations
  81. GRB 241108A: COLIBRÍ Upper Limits on the Optical Counterpart
  82. GRB 241108A : a likely weak long GRB detected by SVOM/ECLAIRs
  83. GRB 241025A: radio detection with the VLA
  84. GRB 241104A: CALET Gamma-Ray Burst Monitor detection
  85. GRB 241107A: SVOM/GRM detection of a short burst
  86. GRB 241105A: EP-FXT follow-up observations
  87. GRB 241105A: SVOM/GRM observation
  88. GRB 241105a: PRIME near-infrared upper limits
  89. GRB 241105A: ePESSTO+ NTT optical afterglow detection
  90. GRB 241025A: LBT optical observations
  91. GRB241105A: Gemini-South Optical Afterglow Detection
  92. GRB 241105A: VLT/FORS2 optical afterglow rapid fading
  93. GRB 241105A: Swift/UVOT Detection
  94. EP241101a: CrAO ZTSH optical observations
  95. GRB 241105A: Swift/BAT-GUANO refined analysis of short burst with extended emission
  96. GRB 241030A: optical afterglow detection from the INAF Asiago Observatory
  97. GRB 241105A: BOOTES-7 optical detection
  98. GRB 241030A: Mondy optical observations
  99. GRB 241105A: Fermi GBM Observation of a Short Burst with Extended Emission
  100. Konus-Wind detection of GRB 241105A (short with extended emission)

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