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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"

27774 results found.

  1. EP241113a: No Detection in Fermi-GBM Observations
  2. Swift GRB 241115A: Global MASTER-Net observations report
  3. GRB 241115A: Swift detection of a burst
  4. GRB 241115A: Fermi GBM Final Real-time Localization
  5. LIGO/Virgo/KAGRA S241114bi: Upper limits from Fermi-GBM Observations
  6. GRB 241113A: Swift-BAT refined analysis
  7. GRB 241113A: PRIME near-infrared upper limits
  8. GRB 241114A: Fermi GBM Final Real-time Localization
  9. GRB 241113A: J-band observations with WINTER
  10. GRB 241030A: LCO optical observation
  11. GRB 241113B: Swift-XRT observations
  12. GRB 241113A: 1.6m Mephisto and 50cm array optical upper limits
  13. GRB 241113A: KAIT optical observations
  14. EP241113b/GRB 241113B: EP detection of GRB 241113B
  15. EP241113a: EP on-board trigger and autonomous follow-up observation
  16. GRB 241113A: Swift-XRT refined Analysis
  17. GRB 241113A: Swift/UVOT Detection
  18. GRB 241113A: REM detection of the optical/NIR afterglow
  19. Konus-Wind detection of GRB 241107A (short/hard)
  20. GRB 241113B: Swift ToO observations
  21. GRB 241113A: LCO optical observations
  22. IceCube-241113A - IceCube observation of a high-energy neutrino candidate track-like event
  23. GRB 241113A: Enhanced Swift-XRT position
  24. GRB241113A: LCOGT (40-cm) optical counterpart detection
  25. GRB 241113B : detection of a long GRB by SVOM/ECLAIRs
  26. GRB 241113A: MASTER010615.66-224018.2 optical counterpart detection
  27. GRB 241113A: Swift detection of a burst with an optical counterpart
  28. Swift GRB241113.33: Global MASTER-Net observations report
  29. SVOM/GRM detection of a short burst from SGR 1E1841-045
  30. GRB 241107A: GROWTH-India telescope optical upper limit
  31. Fermi-GBM Sub-Threshold Detection of GRB 241112B
  32. GRB 241112B: Optical afterglow detection confirmation in revisiting the Mephisto data
  33. GRB 241112B: Swift-XRT afterglow detection
  34. GRB 241112B: LCO optical detection of the SVOM/VT candidate
  35. GRB 241112B: SVOM/VT afterglow detection
  36. GRB 241107A: Swift/BAT candidate arcminute localization of a short burst
  37. GRB 241112B: Swift ToO observations
  38. GRB 241112B : detection of a long GRB by SVOM/ECLAIRs
  39. GRB 241107A: INTEGRAL IBIS localization
  40. GRB 241112A: Fermi GBM Final Real-time Localization
  41. IPN triangulation of GRB 241107A (short/hard)
  42. GRB 241107A: INTEGRAL/IBIS/PICsIT detection of a short burst
  43. GRB 241025C: VZLUSAT-2 detection
  44. GRB 241025A: VZLUSAT-2 detection
  45. GRB 241018A: cubesat Avion detection
  46. GRB 241111A: Fermi GBM Final Real-time Localization
  47. GRB 241030B: TESS detection of optical counterpart
  48. INTEGRAL detection of a burst from 1E 1841-045
  49. LIGO/Virgo/KAGRA S241109bn: Upper limits from Fermi-GBM Observations
  50. EP241109a: confirmation of a stellar flare by BOOTES-7
  51. EP241109a: EP on-board trigger and autonomous follow-up observation
  52. GRB 241108A: Swift-XRT observations
  53. GRB 241108A: Swift ToO observations
  54. GRB 241030A: TESS observations
  55. GRB 241108A : a likely weak long GRB detected by SVOM/ECLAIRs
  56. GRB 241025A: radio detection with the VLA
  57. GRB 241104A: CALET Gamma-Ray Burst Monitor detection
  58. EP241107a: GSP detects optical counterpart
  59. EP241107a: Gemini-South spectroscopic confirmation (z = 0.456)
  60. GRB 241107A: SVOM/GRM detection of a short burst
  61. GRB 241105A: EP-FXT follow-up observations
  62. GRB 241105A: SVOM/GRM observation
  63. EP241107a: OHP/T193 photometric and spectroscopic observations
  64. GRB 241105a: PRIME near-infrared upper limits
  65. GRB 241105A: ePESSTO+ NTT optical afterglow detection
  66. EP241107a: AKO Optical Afterglow Detection
  67. GRB241105A: Gemini-South Optical Afterglow Detection
  68. EP241107a: EP on-board trigger and autonomous follow-up observation
  69. GRB 241105A: Swift/UVOT Detection
  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 241105A: Fermi GBM Observation of a Short Burst with Extended Emission
  74. Konus-Wind detection of GRB 241105A (short with extended emission)
  75. Konus-Wind detection of GRB 241021A
  76. GRB 241105A: Swift-XRT afterglow detection
  77. GRB 241105A: VLT/FORS2 spectroscopic redshift z = 2.681
  78. GRB 241104A: Swift-XRT observations
  79. GRB 240511A: LCO upper limits
  80. GRB 241105A: Swift ToO observations
  81. GRB 241105A: Swift/BAT-GUANO arcminute localization of a short burst
  82. GRB 241104A: Swift ToO observations
  83. GRB 241104A: NOT optical non-detection
  84. GRB 241105A: Fermi GBM Final Real-time Localization
  85. EP241104a: EP detection of GRB 241104A X-ray emission
  86. EP241101a NUTTelA-TAO / BSTI Measurements 2024-11-02
  87. GRB 241104A : Detection and localization by SVOM/ECLAIRs
  88. GRB 241104A: Fermi GBM Final Real-time Localization
  89. GRB 241030A: GRBAlpha detection
  90. EP241101a: EP-FXT observations update
  91. EP241103a: GIT optical upper limit
  92. LIGO/Virgo/KAGRA S241104a: Retraction of GW compact binary merger candidate
  93. EP241103a: GOTO optical upper limit
  94. EP241101a: Possible detection of an optical counterpart with FTW
  95. EP241103a: Swift XRT detection and improved X-ray position
  96. EP241101a: OHP/T193 optical observations
  97. LIGO/Virgo/KAGRA S241102br: MASTER observations and OT detection
  98. LIGO/Virgo/KAGRA S241102br: EP-WXT X-ray follow-up and flux limits
  99. GRB 241030A: Swift-UVOT observations of the optical prompt flare
  100. EP241103a: GSP optical upper limit

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