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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"

45477 results found.

  1. EP241107a: AKO Optical Afterglow Detection
  2. GRB 241025A: LBT optical observations
  3. GRB241105A: Gemini-South Optical Afterglow Detection
  4. EP241107a: EP on-board trigger and autonomous follow-up observation
  5. GRB 241105A: VLT/FORS2 optical afterglow rapid fading
  6. GRB 241105A: Swift/UVOT Detection
  7. EP241101a: CrAO ZTSH optical observations
  8. GRB 241105A: Swift/BAT-GUANO refined analysis of short burst with extended emission
  9. GRB 241030A: optical afterglow detection from the INAF Asiago Observatory
  10. GRB 241105A: BOOTES-7 optical detection
  11. GRB 241030A: Mondy optical observations
  12. GRB 241105A: Fermi GBM Observation of a Short Burst with Extended Emission
  13. Konus-Wind detection of GRB 241105A (short with extended emission)
  14. LIGO/Virgo/KAGRA S241106ba: 1 counterpart neutrino candidate event from an IceCube neutrino search
  15. LIGO/Virgo/KAGRA S241102o: 1 counterpart neutrino candidate event from an IceCube neutrino search
  16. Konus-Wind detection of GRB 241021A
  17. GRB 241105A: SVOM/VT optical afterglow observations
  18. GRB 241105A: Swift-XRT afterglow detection
  19. GRB 241105A: VLT/FORS2 spectroscopic redshift z = 2.681
  20. GRB 241104A: Swift-XRT observations
  21. GRB 240511A: LCO upper limits
  22. GRB 241104A: Fermi GBM Observation
  23. GRB 241104A: The SVOM/VT candidate in GCN circular 38086 is not an astrophysical source
  24. GRB 241105A: Swift ToO observations
  25. GRB 241105A: Swift/BAT-GUANO arcminute localization of a short burst
  26. GRB 241104A: Swift ToO observations
  27. GRB 241104A: NOT optical non-detection
  28. GRB 241105A: GOTO tentative optical counterpart candidate
  29. Fermi GRB 241105A: Global MASTER-Net observations report
  30. GRB 241104A: SVOM/VT optical candidate
  31. GRB 241105A: Fermi GBM Final Real-time Localization
  32. GRB 241104A/EP241104a: Optical upper limits with Kinder observations
  33. GRB 241104A: COLIBRÍ Upper Limits on the Optical Counterpart
  34. GRB 241104A: SVOM/GRM observation
  35. EP241104a: EP detection of GRB 241104A X-ray emission
  36. GRB 241010A: host galaxy redshift z = 0.977
  37. EP241101a NUTTelA-TAO / BSTI Measurements 2024-11-02
  38. GRB 241104A : Detection and localization by SVOM/ECLAIRs
  39. GRB 240821A: further radio observations with the VLA
  40. Fermi GRB 241104A: Global MASTER-Net observations report
  41. GRB 241104A: Fermi GBM Final Real-time Localization
  42. GRB 241030A: GRBAlpha detection
  43. EP241101a: EP-FXT observations update
  44. EP241103a: GIT optical upper limit
  45. EP241021a: OHP/T193 further optical observations
  46. LIGO/Virgo/KAGRA S241104a: Retraction of GW compact binary merger candidate
  47. Fermi trigger No 752365806: Global MASTER-Net observations report
  48. LIGO/Virgo/KAGRA S241102br: OHP/T193 optical observations
  49. LIGO/Virgo/KAGRA S241102cy: Updated Sky localization
  50. EP241103a: GOTO optical upper limit
  51. LIGO/Virgo/KAGRA S241102br: Updated Sky localization
  52. EP241101a: Possible detection of an optical counterpart with FTW
  53. EP241103a: Swift XRT detection and improved X-ray position
  54. EP241021a: continued SOAR observations
  55. EP241101a: Optical upper limits with Kinder observations
  56. EP241101a: OHP/T193 optical observations
  57. EP241103a: Gemini optical limits
  58. EP241103a: EP observation update
  59. LIGO/Virgo/KAGRA S241102br: MASTER observations and OT detection
  60. LIGO/Virgo/KAGRA S241102br: EP-WXT X-ray follow-up and flux limits
  61. GRB 241030A: Swift-UVOT observations of the optical prompt flare
  62. EP241103a: GSP optical upper limit
  63. EP241103A: LCO optical observations
  64. EP241103a: Global MASTER-Net observations report
  65. EP241103a: an X-ray transient detected by Einstein Probe
  66. GRB 241030A: Rapid release of TESS data.
  67. EP241101a: Global MASTER-Net observations report
  68. GRB 241029A: GRBAlpha detection
  69. EP241101a: BOOTES-7 optical upper limit
  70. LIGO/Virgo/KAGRA S241101ee: Updated Sky localization
  71. S241102cy: Identification of a GW compact binary merger candidate
  72. LIGO/Virgo/KAGRA S241102br: NED Galaxies in the Localization Volume
  73. LIGO/Virgo/KAGRA S241102br: Identification of a GW compact binary merger candidate
  74. Kinder optical follow-up observations of EP241021a, EP241026b, and EP241030a/GRB241030A
  75. GRB241030A: OHP/T193 optical observations
  76. EP241030a: Futher EP-FXT observation of the X-ray Afterglow of GRB 241030A
  77. EP241101a: EP-WXT detection of a fast X-ray transient
  78. Swift GRB 241101A: Global MASTER-Net observations report
  79. GRB 241101A: FRAM-ORM optical limit
  80. LIGO/Virgo/KAGRA S241101ee: Identification of a GW compact binary merger candidate
  81. GRB 241030A/EP241030a: TNOT observations of the optical counterpart
  82. EP241021a: Upper limit from Konus-Wind observations
  83. GRB 241101A: Swift-BAT refined analysis
  84. GRB 241030A: further SAO RAS optical observations
  85. GRB 241030A: Optical Observations via Virtual Telescope Project
  86. EP241021a: Liverpool Telescope optical follow-up observations
  87. GRB 241030B: Swift-XRT refined Analysis
  88. GRB 241026A: SAO RAS optical observations
  89. GRB 241030A / EP241030a: GMG possible spectroscopic redshift at z ~ 1.4
  90. EP241030a: EP/FXT observation of GRB 241030A X-ray Afterglow
  91. GRB 241101A: Swift detection of a burst
  92. GRB 241030B: NUTTelA-TAO / BSTI Optical Limits (duplicate submission of 38023)
  93. GRB 241030B: NUTTelA-TAO / BSTI Optical Limits
  94. EP241021a: OHP/T193 optical observations
  95. GRB 241030A: Palomar 1-m telescope COSMOS optical observations
  96. GRB 241030B: Montarrenti Observatory optical upper limit
  97. GRB 241030A / EP241030a: FTW Optical and NIR observations of the optical counterpart
  98. EP241026b: Liverpool Telescope optical follow-up
  99. Fermi trigger No 752083996: Global MASTER-Net observations report
  100. GRB 241030A: SAO RAS optical observations

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