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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"

2407 results found.

  1. GRB 241127A: GRANDMA and Kilonova-Catcher optical afterglow detections
  2. GRB 241127A: SVOM/GRM observation
  3. SVOM/GRM observation of GRB 241126B or a short burst from magnetar
  4. GRB 241126A: SVOM/GRM observation
  5. LIGO/Virgo/KAGRA S241125n: COLIBRÍ Upper Limits on Optical Counterparts to Two of the Swift/XRT Sources
  6. GRB 241113B: EP-FXT afterglow detection
  7. SVOM/GRM detection of a short burst from SGR 1830
  8. Konus-Wind detection of GRB 241115D / EP 241115a
  9. GRB 241026A: radio detection with the VLA
  10. LIGO/Virgo/KAGRA S241125n: COLIBRÍ Upper Limits on a Optical Counterpart at the BAT Position
  11. GRB 241113B: SVOM/VT optical afterglow observations
  12. Konus-Wind detection of GRB 241117A
  13. GRB 241105A: ATCA radio detection
  14. IPN triangulation of GRB 241117A
  15. GRB 241025A: VIRT Optical Upper Limit
  16. GRB 241112B: Mephisto further optical observations
  17. GRB 241117A: Swift/BAT-GUANO localization skymap of a burst
  18. GRB 241117A: SVOM/GRM observation of a short burst with extended emission
  19. EP241115a/GRB 241115D: Optical upper limits with Kinder observations
  20. GRB 241113B: Mephisto upper limits
  21. GRB 241115D / EP 241115a: SVOM/GRM observation
  22. GRB 241113B: KAIT Optical Afterglow Candidate
  23. GRB 241113B: J-band upper limit from WINTER
  24. GRB 241113B: Swift-XRT observations
  25. EP241113b/GRB 241113B: EP detection of GRB 241113B
  26. GRB 241113B: SVOM/GRM observation
  27. EP241107a: SOAR upper limits
  28. Konus-Wind detection of GRB 241107A (short/hard)
  29. GRB 241113B: Swift ToO observations
  30. GRB 241112B: GMG Optical Upper Limit
  31. GRB 241113B : detection of a long GRB by SVOM/ECLAIRs
  32. SVOM/GRM detection of a short burst from SGR 1E1841-045
  33. GRB 241105A: ATCA Radio Upper Limits
  34. GRB 241112B: AbAO optical upper limit
  35. GRB 241107A: GROWTH-India telescope optical upper limit
  36. Fermi-GBM Sub-Threshold Detection of GRB 241112B
  37. GRB 241112B: Optical afterglow detection confirmation in revisiting the Mephisto data
  38. GRB 241112B: Swift-XRT afterglow detection
  39. GRB 241112B: LCO optical detection of the SVOM/VT candidate
  40. GRB 241112B: SVOM/GRM observation
  41. GRB 241112B: SVOM/VT afterglow detection
  42. GRB 241107A: Swift/BAT candidate arcminute localization of a short burst
  43. GRB 241112B: Mephisto optical upper limits
  44. GRB 241112B: GOTO optical upper limits
  45. GRB 241112B: Swift ToO observations
  46. GRB 241112B : detection of a long GRB by SVOM/ECLAIRs
  47. GRB 241107A: INTEGRAL IBIS localization
  48. IPN triangulation of GRB 241107A (short/hard)
  49. GRB 241107A: INTEGRAL/IBIS/PICsIT detection of a short burst
  50. GRB 241025A: VZLUSAT-2 detection
  51. GRB 241018A: cubesat Avion detection
  52. EP241107a: AbAO optical upper limit
  53. GRB 241108A: Further COLIBRÍ Upper Limits on the Optical Counterpart
  54. GRB 241108A: Swift-XRT observations
  55. EP241107A: MASTER optical observations of xray transient
  56. EP241107a: KAIT optical observations
  57. GRB 241108A: Swift ToO observations
  58. GRB 241108A: COLIBRÍ Upper Limits on the Optical Counterpart
  59. GRB 241108A : a likely weak long GRB detected by SVOM/ECLAIRs
  60. EP241107a: Kinder optical follow-up observations
  61. GRB 241025A: radio detection with the VLA
  62. GRB 241104A: CALET Gamma-Ray Burst Monitor detection
  63. GRB 241107A: SVOM/GRM detection of a short burst
  64. GRB 241105A: EP-FXT follow-up observations
  65. GRB 241105A: SVOM/GRM observation
  66. EP241107a: GIT optical observations
  67. EP241107a: SVOM/C-GFT optical observations
  68. GRB 241025A: LBT optical observations
  69. GRB 241105A: VLT/FORS2 optical afterglow rapid fading
  70. GRB 241105A: Swift/BAT-GUANO refined analysis of short burst with extended emission
  71. GRB 241030A: optical afterglow detection from the INAF Asiago Observatory
  72. GRB 241105A: BOOTES-7 optical detection
  73. GRB 241030A: Mondy optical observations
  74. GRB 241105A: Fermi GBM Observation of a Short Burst with Extended Emission
  75. GRB 241105A: SVOM/VT optical afterglow observations
  76. GRB 241104A: Swift-XRT observations
  77. GRB 241104A: Fermi GBM Observation
  78. GRB 241104A: The SVOM/VT candidate in GCN circular 38086 is not an astrophysical source
  79. GRB 241104A: SVOM/VT optical candidate
  80. GRB 241104A/EP241104a: Optical upper limits with Kinder observations
  81. GRB 241104A: COLIBRÍ Upper Limits on the Optical Counterpart
  82. GRB 241104A: SVOM/GRM observation
  83. GRB 241104A : Detection and localization by SVOM/ECLAIRs
  84. GRB 240821A: further radio observations with the VLA
  85. GRB 241030A: GRBAlpha detection
  86. GRB 241029A: GRBAlpha detection
  87. GRB 241030A / EP241030a: GMG possible spectroscopic redshift at z ~ 1.4
  88. GRB 241030B: Montarrenti Observatory optical upper limit
  89. GRB 241030A: Fermi GBM Observation
  90. GRB 241029A: COLIBRI Detection of the Optical Counterpart
  91. GRB 241030B: SVOM/GRM observation
  92. GRB 241030A: COLIBRI Continuing Detection of the Afterglow
  93. GRB 241030B: SVOM/VT optical afterglow observations
  94. GRB 241030B: COLIBRÍ Upper Limits on the Optical Counterpart
  95. GRB241030B: Fermi GBM Observation
  96. GRB 241029A: SVOM/VT optical afterglow observations
  97. GRB 241030A: detection of the bright optical counterpart in ATLAS forced photometry
  98. GRB 241030B: optical observations from the INAF Asiago Observatory
  99. GRB241030B: GRANDMA/TAROT Upper Limit
  100. GRB 241030B: AKO Optical Afterglow Detection

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