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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"

45493 results found.

  1. EP241107a: Kinder optical follow-up observations
  2. GRB 241025A: radio detection with the VLA
  3. GRB 241104A: CALET Gamma-Ray Burst Monitor detection
  4. EP241107a: AKO Optical Afterglow Follow-Up Observations
  5. EP241107a: GSP detects optical counterpart
  6. EP241107a: Gemini-South spectroscopic confirmation (z = 0.456)
  7. GRB 241107A: SVOM/GRM detection of a short burst
  8. GRB 241105A: EP-FXT follow-up observations
  9. GRB 241105A: SVOM/GRM observation
  10. EP241107a: OHP/T193 photometric and spectroscopic observations
  11. GRB 241105a: PRIME near-infrared upper limits
  12. EP241107a: FTW Optical and NIR observations of the optical counterpart
  13. GRB 241105A: ePESSTO+ NTT optical afterglow detection
  14. EP241107a: GIT optical observations
  15. EP241107a: Global MASTER-Net observations report
  16. EP241107a: SVOM/C-GFT optical observations
  17. EP241107a: AKO Optical Afterglow Detection
  18. GRB 241025A: LBT optical observations
  19. GRB241105A: Gemini-South Optical Afterglow Detection
  20. EP241107a: EP on-board trigger and autonomous follow-up observation
  21. GRB 241105A: VLT/FORS2 optical afterglow rapid fading
  22. GRB 241105A: Swift/UVOT Detection
  23. EP241101a: CrAO ZTSH optical observations
  24. GRB 241105A: Swift/BAT-GUANO refined analysis of short burst with extended emission
  25. GRB 241030A: optical afterglow detection from the INAF Asiago Observatory
  26. GRB 241105A: BOOTES-7 optical detection
  27. GRB 241030A: Mondy optical observations
  28. GRB 241105A: Fermi GBM Observation of a Short Burst with Extended Emission
  29. Konus-Wind detection of GRB 241105A (short with extended emission)
  30. LIGO/Virgo/KAGRA S241106ba: 1 counterpart neutrino candidate event from an IceCube neutrino search
  31. LIGO/Virgo/KAGRA S241102o: 1 counterpart neutrino candidate event from an IceCube neutrino search
  32. Konus-Wind detection of GRB 241021A
  33. GRB 241105A: SVOM/VT optical afterglow observations
  34. GRB 241105A: Swift-XRT afterglow detection
  35. GRB 241105A: VLT/FORS2 spectroscopic redshift z = 2.681
  36. GRB 241104A: Swift-XRT observations
  37. GRB 240511A: LCO upper limits
  38. GRB 241104A: Fermi GBM Observation
  39. GRB 241104A: The SVOM/VT candidate in GCN circular 38086 is not an astrophysical source
  40. GRB 241105A: Swift ToO observations
  41. GRB 241105A: Swift/BAT-GUANO arcminute localization of a short burst
  42. GRB 241104A: Swift ToO observations
  43. GRB 241104A: NOT optical non-detection
  44. GRB 241105A: GOTO tentative optical counterpart candidate
  45. Fermi GRB 241105A: Global MASTER-Net observations report
  46. GRB 241104A: SVOM/VT optical candidate
  47. GRB 241105A: Fermi GBM Final Real-time Localization
  48. GRB 241104A/EP241104a: Optical upper limits with Kinder observations
  49. GRB 241104A: COLIBRÍ Upper Limits on the Optical Counterpart
  50. GRB 241104A: SVOM/GRM observation
  51. EP241104a: EP detection of GRB 241104A X-ray emission
  52. GRB 241010A: host galaxy redshift z = 0.977
  53. EP241101a NUTTelA-TAO / BSTI Measurements 2024-11-02
  54. GRB 241104A : Detection and localization by SVOM/ECLAIRs
  55. GRB 240821A: further radio observations with the VLA
  56. Fermi GRB 241104A: Global MASTER-Net observations report
  57. GRB 241104A: Fermi GBM Final Real-time Localization
  58. GRB 241030A: GRBAlpha detection
  59. EP241101a: EP-FXT observations update
  60. EP241103a: GIT optical upper limit
  61. EP241021a: OHP/T193 further optical observations
  62. LIGO/Virgo/KAGRA S241104a: Retraction of GW compact binary merger candidate
  63. Fermi trigger No 752365806: Global MASTER-Net observations report
  64. LIGO/Virgo/KAGRA S241102br: OHP/T193 optical observations
  65. LIGO/Virgo/KAGRA S241102cy: Updated Sky localization
  66. EP241103a: GOTO optical upper limit
  67. LIGO/Virgo/KAGRA S241102br: Updated Sky localization
  68. EP241101a: Possible detection of an optical counterpart with FTW
  69. EP241103a: Swift XRT detection and improved X-ray position
  70. EP241021a: continued SOAR observations
  71. EP241101a: Optical upper limits with Kinder observations
  72. EP241101a: OHP/T193 optical observations
  73. EP241103a: Gemini optical limits
  74. EP241103a: EP observation update
  75. LIGO/Virgo/KAGRA S241102br: MASTER observations and OT detection
  76. LIGO/Virgo/KAGRA S241102br: EP-WXT X-ray follow-up and flux limits
  77. GRB 241030A: Swift-UVOT observations of the optical prompt flare
  78. EP241103a: GSP optical upper limit
  79. EP241103A: LCO optical observations
  80. EP241103a: Global MASTER-Net observations report
  81. EP241103a: an X-ray transient detected by Einstein Probe
  82. GRB 241030A: Rapid release of TESS data.
  83. EP241101a: Global MASTER-Net observations report
  84. GRB 241029A: GRBAlpha detection
  85. EP241101a: BOOTES-7 optical upper limit
  86. LIGO/Virgo/KAGRA S241101ee: Updated Sky localization
  87. S241102cy: Identification of a GW compact binary merger candidate
  88. LIGO/Virgo/KAGRA S241102br: NED Galaxies in the Localization Volume
  89. LIGO/Virgo/KAGRA S241102br: Identification of a GW compact binary merger candidate
  90. Kinder optical follow-up observations of EP241021a, EP241026b, and EP241030a/GRB241030A
  91. GRB241030A: OHP/T193 optical observations
  92. EP241030a: Futher EP-FXT observation of the X-ray Afterglow of GRB 241030A
  93. EP241101a: EP-WXT detection of a fast X-ray transient
  94. Swift GRB 241101A: Global MASTER-Net observations report
  95. GRB 241101A: FRAM-ORM optical limit
  96. LIGO/Virgo/KAGRA S241101ee: Identification of a GW compact binary merger candidate
  97. GRB 241030A/EP241030a: TNOT observations of the optical counterpart
  98. EP241021a: Upper limit from Konus-Wind observations
  99. GRB 241101A: Swift-BAT refined analysis
  100. GRB 241030A: further SAO RAS optical observations

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