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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"
  1. EP241107a: AbAO optical upper limit
  2. LIGO/Virgo/KAGRA S241109bn: Upper limits from Fermi-GBM Observations
  3. GRB 241108A: Further COLIBRÍ Upper Limits on the Optical Counterpart
  4. LIGO/Virgo/KAGRA S241109p: Updated Sky localization and Source Classification
  5. LIGO/Virgo/KAGRA S241109bn: Global MASTER-Net observations report
  6. LIGO/Virgo/KAGRA S241109bn: Identification of a GW compact binary merger candidate
  7. EP241109a: confirmation of a stellar flare by BOOTES-7
  8. EP241109a: EP on-board trigger and autonomous follow-up observation
  9. GRB 241108A: Swift-XRT observations
  10. LIGO/Virgo/KAGRA S241109p: Identification of a GW compact binary merger candidate
  11. EP241107A: MASTER optical observations of xray transient
  12. EP241107a: KAIT optical observations
  13. GRB 241108A: Swift ToO observations
  14. GRB 241030A: TESS observations
  15. GRB 241108A: COLIBRÍ Upper Limits on the Optical Counterpart
  16. GRB 241108A : a likely weak long GRB detected by SVOM/ECLAIRs
  17. EP241107a: Kinder optical follow-up observations
  18. GRB 241025A: radio detection with the VLA
  19. GRB 241104A: CALET Gamma-Ray Burst Monitor detection
  20. EP241107a: AKO Optical Afterglow Follow-Up Observations
  21. EP241107a: GSP detects optical counterpart
  22. EP241107a: Gemini-South spectroscopic confirmation (z = 0.456)
  23. GRB 241107A: SVOM/GRM detection of a short burst
  24. GRB 241105A: EP-FXT follow-up observations
  25. GRB 241105A: SVOM/GRM observation
  26. EP241107a: OHP/T193 photometric and spectroscopic observations
  27. GRB 241105a: PRIME near-infrared upper limits
  28. EP241107a: FTW Optical and NIR observations of the optical counterpart
  29. GRB 241105A: ePESSTO+ NTT optical afterglow detection
  30. EP241107a: GIT optical observations
  31. EP241107a: Global MASTER-Net observations report
  32. EP241107a: SVOM/C-GFT optical observations
  33. EP241107a: AKO Optical Afterglow Detection
  34. GRB 241025A: LBT optical observations
  35. GRB241105A: Gemini-South Optical Afterglow Detection
  36. EP241107a: EP on-board trigger and autonomous follow-up observation
  37. GRB 241105A: VLT/FORS2 optical afterglow rapid fading
  38. GRB 241105A: Swift/UVOT Detection
  39. EP241101a: CrAO ZTSH optical observations
  40. GRB 241105A: Swift/BAT-GUANO refined analysis of short burst with extended emission
  41. GRB 241030A: optical afterglow detection from the INAF Asiago Observatory
  42. GRB 241105A: BOOTES-7 optical detection
  43. GRB 241030A: Mondy optical observations
  44. GRB 241105A: Fermi GBM Observation of a Short Burst with Extended Emission
  45. Konus-Wind detection of GRB 241105A (short with extended emission)
  46. LIGO/Virgo/KAGRA S241106ba: 1 counterpart neutrino candidate event from an IceCube neutrino search
  47. LIGO/Virgo/KAGRA S241102o: 1 counterpart neutrino candidate event from an IceCube neutrino search
  48. Konus-Wind detection of GRB 241021A
  49. GRB 241105A: SVOM/VT optical afterglow observations
  50. GRB 241105A: Swift-XRT afterglow detection
  51. GRB 241105A: VLT/FORS2 spectroscopic redshift z = 2.681
  52. GRB 241104A: Swift-XRT observations
  53. GRB 240511A: LCO upper limits
  54. GRB 241104A: Fermi GBM Observation
  55. GRB 241104A: The SVOM/VT candidate in GCN circular 38086 is not an astrophysical source
  56. GRB 241105A: Swift ToO observations
  57. GRB 241105A: Swift/BAT-GUANO arcminute localization of a short burst
  58. GRB 241104A: Swift ToO observations
  59. GRB 241104A: NOT optical non-detection
  60. GRB 241105A: GOTO tentative optical counterpart candidate
  61. Fermi GRB 241105A: Global MASTER-Net observations report
  62. GRB 241104A: SVOM/VT optical candidate
  63. GRB 241105A: Fermi GBM Final Real-time Localization
  64. GRB 241104A/EP241104a: Optical upper limits with Kinder observations
  65. GRB 241104A: COLIBRÍ Upper Limits on the Optical Counterpart
  66. GRB 241104A: SVOM/GRM observation
  67. EP241104a: EP detection of GRB 241104A X-ray emission
  68. GRB 241010A: host galaxy redshift z = 0.977
  69. EP241101a NUTTelA-TAO / BSTI Measurements 2024-11-02
  70. GRB 241104A : Detection and localization by SVOM/ECLAIRs
  71. GRB 240821A: further radio observations with the VLA
  72. Fermi GRB 241104A: Global MASTER-Net observations report
  73. GRB 241104A: Fermi GBM Final Real-time Localization
  74. GRB 241030A: GRBAlpha detection
  75. EP241101a: EP-FXT observations update
  76. EP241103a: GIT optical upper limit
  77. EP241021a: OHP/T193 further optical observations
  78. LIGO/Virgo/KAGRA S241104a: Retraction of GW compact binary merger candidate
  79. Fermi trigger No 752365806: Global MASTER-Net observations report
  80. LIGO/Virgo/KAGRA S241102br: OHP/T193 optical observations
  81. LIGO/Virgo/KAGRA S241102cy: Updated Sky localization
  82. EP241103a: GOTO optical upper limit
  83. LIGO/Virgo/KAGRA S241102br: Updated Sky localization
  84. EP241101a: Possible detection of an optical counterpart with FTW
  85. EP241103a: Swift XRT detection and improved X-ray position
  86. EP241021a: continued SOAR observations
  87. EP241101a: Optical upper limits with Kinder observations
  88. EP241101a: OHP/T193 optical observations
  89. EP241103a: Gemini optical limits
  90. EP241103a: EP observation update
  91. LIGO/Virgo/KAGRA S241102br: MASTER observations and OT detection
  92. LIGO/Virgo/KAGRA S241102br: EP-WXT X-ray follow-up and flux limits
  93. GRB 241030A: Swift-UVOT observations of the optical prompt flare
  94. EP241103a: GSP optical upper limit
  95. EP241103A: LCO optical observations
  96. EP241103a: Global MASTER-Net observations report
  97. EP241103a: an X-ray transient detected by Einstein Probe
  98. GRB 241030A: Rapid release of TESS data.
  99. EP241101a: Global MASTER-Net observations report
  100. GRB 241029A: GRBAlpha detection

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