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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"

39182 results found.

  1. GRB 241113A: Enhanced Swift-XRT position
  2. GRB241113A: LCOGT (40-cm) optical counterpart detection
  3. GRB 241113B : detection of a long GRB by SVOM/ECLAIRs
  4. GRB 241113A: MASTER010615.66-224018.2 optical counterpart detection
  5. GRB 241113A: Swift detection of a burst with an optical counterpart
  6. Swift GRB241113.33: Global MASTER-Net observations report
  7. SVOM/GRM detection of a short burst from SGR 1E1841-045
  8. Fermi trigger No 753166198: Global MASTER-Net observations report
  9. GRB 241105A: ATCA Radio Upper Limits
  10. GRB 241112B: AbAO optical upper limit
  11. GRB 241107A: GROWTH-India telescope optical upper limit
  12. IceCube Alert 241113.02: Global MASTER-Net observations report
  13. Fermi GRB 241112A: Global MASTER-Net observations report
  14. Fermi-GBM Sub-Threshold Detection of GRB 241112B
  15. GRB 241112B: Optical afterglow detection confirmation in revisiting the Mephisto data
  16. GRB 241112B: Swift-XRT afterglow detection
  17. GRB 241112B: LCO optical detection of the SVOM/VT candidate
  18. GRB 241112B: SVOM/GRM observation
  19. GRB 241112B: SVOM/VT afterglow detection
  20. Fermi Gamma-ray Burst Monitor trigger 752995908/241111230 (GRB 241111A) is not a GRB
  21. GRB 241107A: Swift/BAT candidate arcminute localization of a short burst
  22. GRB 241112B: Mephisto optical upper limits
  23. GRB 241112B: GOTO optical upper limits
  24. GRB 241112B: Swift ToO observations
  25. GRB 241112B : detection of a long GRB by SVOM/ECLAIRs
  26. GRB 241107A: INTEGRAL IBIS localization
  27. GRB 241112A: Fermi GBM Final Real-time Localization
  28. GRB 241105A: VLT/FORS2 refined spectroscopic redshift z = 2.681
  29. IPN triangulation of GRB 241107A (short/hard)
  30. GRB 241107A: INTEGRAL/IBIS/PICsIT detection of a short burst
  31. GRB 241025C: VZLUSAT-2 detection
  32. GRB 241025A: VZLUSAT-2 detection
  33. GRB 241018A: cubesat Avion detection
  34. Fermi trigger No 752990530: Global MASTER-Net observations report
  35. GRB 241111A: Fermi GBM Final Real-time Localization
  36. GRB 241030B: TESS detection of optical counterpart
  37. Fermi trigger No 752878030: Global MASTER-Net observations report
  38. Integral GRB241109.89: Global MASTER-Net observations report
  39. EP241109a: KAIT photometry and 3 m Shane spectroscopy from Lick observatory
  40. EP241107a: AbAO optical upper limit
  41. LIGO/Virgo/KAGRA S241109bn: Upper limits from Fermi-GBM Observations
  42. GRB 241108A: Further COLIBRÍ Upper Limits on the Optical Counterpart
  43. LIGO/Virgo/KAGRA S241109bn: Global MASTER-Net observations report
  44. GRB 241108A: Swift-XRT observations
  45. EP241107A: MASTER optical observations of xray transient
  46. EP241107a: KAIT optical observations
  47. GRB 241108A: Swift ToO observations
  48. GRB 241030A: TESS observations
  49. GRB 241108A: COLIBRÍ Upper Limits on the Optical Counterpart
  50. GRB 241108A : a likely weak long GRB detected by SVOM/ECLAIRs
  51. GRB 241025A: radio detection with the VLA
  52. GRB 241104A: CALET Gamma-Ray Burst Monitor detection
  53. EP241107a: GSP detects optical counterpart
  54. GRB 241107A: SVOM/GRM detection of a short burst
  55. GRB 241105A: EP-FXT follow-up observations
  56. GRB 241105A: SVOM/GRM observation
  57. GRB 241105a: PRIME near-infrared upper limits
  58. GRB 241105A: ePESSTO+ NTT optical afterglow detection
  59. EP241107a: GIT optical observations
  60. EP241107a: Global MASTER-Net observations report
  61. EP241107a: SVOM/C-GFT optical observations
  62. GRB 241025A: LBT optical observations
  63. GRB241105A: Gemini-South Optical Afterglow Detection
  64. GRB 241105A: VLT/FORS2 optical afterglow rapid fading
  65. GRB 241105A: Swift/UVOT Detection
  66. EP241101a: CrAO ZTSH optical observations
  67. GRB 241105A: Swift/BAT-GUANO refined analysis of short burst with extended emission
  68. GRB 241030A: optical afterglow detection from the INAF Asiago Observatory
  69. GRB 241105A: BOOTES-7 optical detection
  70. GRB 241030A: Mondy optical observations
  71. GRB 241105A: Fermi GBM Observation of a Short Burst with Extended Emission
  72. Konus-Wind detection of GRB 241105A (short with extended emission)
  73. Konus-Wind detection of GRB 241021A
  74. GRB 241105A: SVOM/VT optical afterglow observations
  75. GRB 241105A: Swift-XRT afterglow detection
  76. GRB 241105A: VLT/FORS2 spectroscopic redshift z = 2.681
  77. GRB 241104A: Swift-XRT observations
  78. GRB 240511A: LCO upper limits
  79. GRB 241104A: Fermi GBM Observation
  80. GRB 241104A: The SVOM/VT candidate in GCN circular 38086 is not an astrophysical source
  81. GRB 241105A: Swift ToO observations
  82. GRB 241105A: Swift/BAT-GUANO arcminute localization of a short burst
  83. GRB 241104A: Swift ToO observations
  84. GRB 241104A: NOT optical non-detection
  85. GRB 241105A: GOTO tentative optical counterpart candidate
  86. Fermi GRB 241105A: Global MASTER-Net observations report
  87. GRB 241104A: SVOM/VT optical candidate
  88. GRB 241105A: Fermi GBM Final Real-time Localization
  89. GRB 241104A/EP241104a: Optical upper limits with Kinder observations
  90. GRB 241104A: COLIBRÍ Upper Limits on the Optical Counterpart
  91. GRB 241104A: SVOM/GRM observation
  92. EP241104a: EP detection of GRB 241104A X-ray emission
  93. GRB 241010A: host galaxy redshift z = 0.977
  94. GRB 241104A : Detection and localization by SVOM/ECLAIRs
  95. GRB 240821A: further radio observations with the VLA
  96. Fermi GRB 241104A: Global MASTER-Net observations report
  97. GRB 241104A: Fermi GBM Final Real-time Localization
  98. GRB 241030A: GRBAlpha detection
  99. EP241103a: GIT optical upper limit
  100. Fermi trigger No 752365806: Global MASTER-Net observations report

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