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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"

44399 results found.

  1. EP241107A: MASTER optical observations of xray transient
  2. EP241107a: KAIT optical observations
  3. GRB 241108A: Swift ToO observations
  4. GRB 241030A: TESS observations
  5. GRB 241108A: COLIBRÍ Upper Limits on the Optical Counterpart
  6. GRB 241108A : a likely weak long GRB detected by SVOM/ECLAIRs
  7. EP241107a: Kinder optical follow-up observations
  8. GRB 241025A: radio detection with the VLA
  9. GRB 241104A: CALET Gamma-Ray Burst Monitor detection
  10. EP241107a: AKO Optical Afterglow Follow-Up Observations
  11. EP241107a: GSP detects optical counterpart
  12. EP241107a: Gemini-South spectroscopic confirmation (z = 0.456)
  13. GRB 241107A: SVOM/GRM detection of a short burst
  14. GRB 241105A: EP-FXT follow-up observations
  15. GRB 241105A: SVOM/GRM observation
  16. EP241107a: OHP/T193 photometric and spectroscopic observations
  17. GRB 241105a: PRIME near-infrared upper limits
  18. EP241107a: FTW Optical and NIR observations of the optical counterpart
  19. GRB 241105A: ePESSTO+ NTT optical afterglow detection
  20. EP241107a: GIT optical observations
  21. EP241107a: Global MASTER-Net observations report
  22. EP241107a: SVOM/C-GFT optical observations
  23. EP241107a: AKO Optical Afterglow Detection
  24. GRB 241025A: LBT optical observations
  25. GRB241105A: Gemini-South Optical Afterglow Detection
  26. EP241107a: EP on-board trigger and autonomous follow-up observation
  27. GRB 241105A: VLT/FORS2 optical afterglow rapid fading
  28. GRB 241105A: Swift/UVOT Detection
  29. EP241101a: CrAO ZTSH optical observations
  30. GRB 241105A: Swift/BAT-GUANO refined analysis of short burst with extended emission
  31. GRB 241030A: optical afterglow detection from the INAF Asiago Observatory
  32. GRB 241105A: BOOTES-7 optical detection
  33. GRB 241030A: Mondy optical observations
  34. GRB 241105A: Fermi GBM Observation of a Short Burst with Extended Emission
  35. Konus-Wind detection of GRB 241105A (short with extended emission)
  36. LIGO/Virgo/KAGRA S241106ba: 1 counterpart neutrino candidate event from an IceCube neutrino search
  37. LIGO/Virgo/KAGRA S241102o: 1 counterpart neutrino candidate event from an IceCube neutrino search
  38. Konus-Wind detection of GRB 241021A
  39. GRB 241105A: SVOM/VT optical afterglow observations
  40. GRB 241105A: Swift-XRT afterglow detection
  41. GRB 241105A: VLT/FORS2 spectroscopic redshift z = 2.681
  42. GRB 241104A: Swift-XRT observations
  43. GRB 240511A: LCO upper limits
  44. GRB 241104A: Fermi GBM Observation
  45. GRB 241104A: The SVOM/VT candidate in GCN circular 38086 is not an astrophysical source
  46. GRB 241105A: Swift ToO observations
  47. GRB 241105A: Swift/BAT-GUANO arcminute localization of a short burst
  48. GRB 241104A: Swift ToO observations
  49. GRB 241104A: NOT optical non-detection
  50. GRB 241105A: GOTO tentative optical counterpart candidate
  51. Fermi GRB 241105A: Global MASTER-Net observations report
  52. GRB 241104A: SVOM/VT optical candidate
  53. GRB 241105A: Fermi GBM Final Real-time Localization
  54. GRB 241104A/EP241104a: Optical upper limits with Kinder observations
  55. GRB 241104A: COLIBRÍ Upper Limits on the Optical Counterpart
  56. GRB 241104A: SVOM/GRM observation
  57. EP241104a: EP detection of GRB 241104A X-ray emission
  58. GRB 241010A: host galaxy redshift z = 0.977
  59. EP241101a NUTTelA-TAO / BSTI Measurements 2024-11-02
  60. GRB 241104A : Detection and localization by SVOM/ECLAIRs
  61. GRB 240821A: further radio observations with the VLA
  62. Fermi GRB 241104A: Global MASTER-Net observations report
  63. GRB 241104A: Fermi GBM Final Real-time Localization
  64. GRB 241030A: GRBAlpha detection
  65. EP241101a: EP-FXT observations update
  66. EP241103a: GIT optical upper limit
  67. EP241021a: OHP/T193 further optical observations
  68. LIGO/Virgo/KAGRA S241104a: Retraction of GW compact binary merger candidate
  69. Fermi trigger No 752365806: Global MASTER-Net observations report
  70. LIGO/Virgo/KAGRA S241102br: OHP/T193 optical observations
  71. LIGO/Virgo/KAGRA S241102cy: Updated Sky localization
  72. EP241103a: GOTO optical upper limit
  73. LIGO/Virgo/KAGRA S241102br: Updated Sky localization
  74. EP241101a: Possible detection of an optical counterpart with FTW
  75. EP241103a: Swift XRT detection and improved X-ray position
  76. EP241021a: continued SOAR observations
  77. EP241101a: Optical upper limits with Kinder observations
  78. EP241101a: OHP/T193 optical observations
  79. EP241103a: Gemini optical limits
  80. EP241103a: EP observation update
  81. LIGO/Virgo/KAGRA S241102br: MASTER observations and OT detection
  82. LIGO/Virgo/KAGRA S241102br: EP-WXT X-ray follow-up and flux limits
  83. GRB 241030A: Swift-UVOT observations of the optical prompt flare
  84. EP241103a: GSP optical upper limit
  85. EP241103A: LCO optical observations
  86. EP241103a: Global MASTER-Net observations report
  87. EP241103a: an X-ray transient detected by Einstein Probe
  88. GRB 241030A: Rapid release of TESS data.
  89. EP241101a: Global MASTER-Net observations report
  90. GRB 241029A: GRBAlpha detection
  91. EP241101a: BOOTES-7 optical upper limit
  92. LIGO/Virgo/KAGRA S241101ee: Updated Sky localization
  93. S241102cy: Identification of a GW compact binary merger candidate
  94. LIGO/Virgo/KAGRA S241102br: NED Galaxies in the Localization Volume
  95. LIGO/Virgo/KAGRA S241102br: Identification of a GW compact binary merger candidate
  96. Kinder optical follow-up observations of EP241021a, EP241026b, and EP241030a/GRB241030A
  97. GRB241030A: OHP/T193 optical observations
  98. EP241030a: Futher EP-FXT observation of the X-ray Afterglow of GRB 241030A
  99. EP241101a: EP-WXT detection of a fast X-ray transient
  100. Swift GRB 241101A: Global MASTER-Net observations report

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