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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"

44271 results found.

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

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