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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. GRB 241108A: Further COLIBRÍ Upper Limits on the Optical Counterpart
  2. LIGO/Virgo/KAGRA S241109p: Updated Sky localization and Source Classification
  3. LIGO/Virgo/KAGRA S241109bn: Global MASTER-Net observations report
  4. LIGO/Virgo/KAGRA S241109bn: Identification of a GW compact binary merger candidate
  5. EP241109a: confirmation of a stellar flare by BOOTES-7
  6. EP241109a: EP on-board trigger and autonomous follow-up observation
  7. GRB 241108A: Swift-XRT observations
  8. LIGO/Virgo/KAGRA S241109p: Identification of a GW compact binary merger candidate
  9. EP241107A: MASTER optical observations of xray transient
  10. EP241107a: KAIT optical observations
  11. GRB 241108A: Swift ToO observations
  12. GRB 241030A: TESS observations
  13. GRB 241108A: COLIBRÍ Upper Limits on the Optical Counterpart
  14. GRB 241108A : a likely weak long GRB detected by SVOM/ECLAIRs
  15. EP241107a: Kinder optical follow-up observations
  16. GRB 241025A: radio detection with the VLA
  17. GRB 241104A: CALET Gamma-Ray Burst Monitor detection
  18. EP241107a: AKO Optical Afterglow Follow-Up Observations
  19. EP241107a: GSP detects optical counterpart
  20. EP241107a: Gemini-South spectroscopic confirmation (z = 0.456)
  21. GRB 241107A: SVOM/GRM detection of a short burst
  22. GRB 241105A: EP-FXT follow-up observations
  23. GRB 241105A: SVOM/GRM observation
  24. EP241107a: OHP/T193 photometric and spectroscopic observations
  25. GRB 241105a: PRIME near-infrared upper limits
  26. EP241107a: FTW Optical and NIR observations of the optical counterpart
  27. GRB 241105A: ePESSTO+ NTT optical afterglow detection
  28. EP241107a: GIT optical observations
  29. EP241107a: Global MASTER-Net observations report
  30. EP241107a: SVOM/C-GFT optical observations
  31. EP241107a: AKO Optical Afterglow Detection
  32. GRB 241025A: LBT optical observations
  33. GRB241105A: Gemini-South Optical Afterglow Detection
  34. EP241107a: EP on-board trigger and autonomous follow-up observation
  35. GRB 241105A: VLT/FORS2 optical afterglow rapid fading
  36. GRB 241105A: Swift/UVOT Detection
  37. EP241101a: CrAO ZTSH optical observations
  38. GRB 241105A: Swift/BAT-GUANO refined analysis of short burst with extended emission
  39. GRB 241030A: optical afterglow detection from the INAF Asiago Observatory
  40. GRB 241105A: BOOTES-7 optical detection
  41. GRB 241030A: Mondy optical observations
  42. GRB 241105A: Fermi GBM Observation of a Short Burst with Extended Emission
  43. Konus-Wind detection of GRB 241105A (short with extended emission)
  44. LIGO/Virgo/KAGRA S241106ba: 1 counterpart neutrino candidate event from an IceCube neutrino search
  45. LIGO/Virgo/KAGRA S241102o: 1 counterpart neutrino candidate event from an IceCube neutrino search
  46. Konus-Wind detection of GRB 241021A
  47. GRB 241105A: SVOM/VT optical afterglow observations
  48. GRB 241105A: Swift-XRT afterglow detection
  49. GRB 241105A: VLT/FORS2 spectroscopic redshift z = 2.681
  50. GRB 241104A: Swift-XRT observations
  51. GRB 240511A: LCO upper limits
  52. GRB 241104A: Fermi GBM Observation
  53. GRB 241104A: The SVOM/VT candidate in GCN circular 38086 is not an astrophysical source
  54. GRB 241105A: Swift ToO observations
  55. GRB 241105A: Swift/BAT-GUANO arcminute localization of a short burst
  56. GRB 241104A: Swift ToO observations
  57. GRB 241104A: NOT optical non-detection
  58. GRB 241105A: GOTO tentative optical counterpart candidate
  59. Fermi GRB 241105A: Global MASTER-Net observations report
  60. GRB 241104A: SVOM/VT optical candidate
  61. GRB 241105A: Fermi GBM Final Real-time Localization
  62. GRB 241104A/EP241104a: Optical upper limits with Kinder observations
  63. GRB 241104A: COLIBRÍ Upper Limits on the Optical Counterpart
  64. GRB 241104A: SVOM/GRM observation
  65. EP241104a: EP detection of GRB 241104A X-ray emission
  66. GRB 241010A: host galaxy redshift z = 0.977
  67. EP241101a NUTTelA-TAO / BSTI Measurements 2024-11-02
  68. GRB 241104A : Detection and localization by SVOM/ECLAIRs
  69. GRB 240821A: further radio observations with the VLA
  70. Fermi GRB 241104A: Global MASTER-Net observations report
  71. GRB 241104A: Fermi GBM Final Real-time Localization
  72. GRB 241030A: GRBAlpha detection
  73. EP241101a: EP-FXT observations update
  74. EP241103a: GIT optical upper limit
  75. EP241021a: OHP/T193 further optical observations
  76. LIGO/Virgo/KAGRA S241104a: Retraction of GW compact binary merger candidate
  77. Fermi trigger No 752365806: Global MASTER-Net observations report
  78. LIGO/Virgo/KAGRA S241102br: OHP/T193 optical observations
  79. LIGO/Virgo/KAGRA S241102cy: Updated Sky localization
  80. EP241103a: GOTO optical upper limit
  81. LIGO/Virgo/KAGRA S241102br: Updated Sky localization
  82. EP241101a: Possible detection of an optical counterpart with FTW
  83. EP241103a: Swift XRT detection and improved X-ray position
  84. EP241021a: continued SOAR observations
  85. EP241101a: Optical upper limits with Kinder observations
  86. EP241101a: OHP/T193 optical observations
  87. EP241103a: Gemini optical limits
  88. EP241103a: EP observation update
  89. LIGO/Virgo/KAGRA S241102br: MASTER observations and OT detection
  90. LIGO/Virgo/KAGRA S241102br: EP-WXT X-ray follow-up and flux limits
  91. GRB 241030A: Swift-UVOT observations of the optical prompt flare
  92. EP241103a: GSP optical upper limit
  93. EP241103A: LCO optical observations
  94. EP241103a: Global MASTER-Net observations report
  95. EP241103a: an X-ray transient detected by Einstein Probe
  96. GRB 241030A: Rapid release of TESS data.
  97. EP241101a: Global MASTER-Net observations report
  98. GRB 241029A: GRBAlpha detection
  99. EP241101a: BOOTES-7 optical upper limit
  100. LIGO/Virgo/KAGRA S241101ee: Updated Sky localization

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