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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"

20967 results found.

  1. Fermi trigger No 752878030: Global MASTER-Net observations report
  2. Integral GRB241109.89: Global MASTER-Net observations report
  3. LIGO/Virgo/KAGRA S241109bn: Coverage and upper limits from MAXI/GSC observations
  4. EP241109a: KAIT photometry and 3 m Shane spectroscopy from Lick observatory
  5. LIGO/Virgo/KAGRA S241109bn: Upper limits from Fermi-GBM Observations
  6. LIGO/Virgo/KAGRA S241109bn: Global MASTER-Net observations report
  7. EP241109a: confirmation of a stellar flare by BOOTES-7
  8. EP241109a: EP on-board trigger and autonomous follow-up observation
  9. GRB 241108A: Swift-XRT observations
  10. EP241107A: MASTER optical observations of xray transient
  11. EP241107a: KAIT optical observations
  12. GRB 241108A: Swift ToO observations
  13. GRB 241030A: TESS observations
  14. EP241107a: Kinder optical follow-up observations
  15. GRB 241025A: radio detection with the VLA
  16. EP241107a: AKO Optical Afterglow Follow-Up Observations
  17. EP241107a: GSP detects optical counterpart
  18. GRB 241105A: EP-FXT follow-up observations
  19. EP241107a: OHP/T193 photometric and spectroscopic observations
  20. GRB 241105a: PRIME near-infrared upper limits
  21. EP241107a: FTW Optical and NIR observations of the optical counterpart
  22. GRB 241105A: ePESSTO+ NTT optical afterglow detection
  23. EP241107a: GIT optical observations
  24. EP241107a: Global MASTER-Net observations report
  25. EP241107a: SVOM/C-GFT optical observations
  26. GRB 241025A: LBT optical observations
  27. GRB241105A: Gemini-South Optical Afterglow Detection
  28. EP241107a: EP on-board trigger and autonomous follow-up observation
  29. GRB 241105A: VLT/FORS2 optical afterglow rapid fading
  30. GRB 241105A: Swift/UVOT Detection
  31. EP241101a: CrAO ZTSH optical observations
  32. GRB 241030A: optical afterglow detection from the INAF Asiago Observatory
  33. GRB 241105A: BOOTES-7 optical detection
  34. GRB 241030A: Mondy optical observations
  35. GRB 241105A: SVOM/VT optical afterglow observations
  36. GRB 241105A: Swift-XRT afterglow detection
  37. GRB 241104A: Swift-XRT observations
  38. GRB 240511A: LCO upper limits
  39. GRB 241105A: Swift ToO observations
  40. GRB 241105A: Swift/BAT-GUANO arcminute localization of a short burst
  41. GRB 241104A: Swift ToO observations
  42. GRB 241104A: NOT optical non-detection
  43. GRB 241105A: GOTO tentative optical counterpart candidate
  44. Fermi GRB 241105A: Global MASTER-Net observations report
  45. GRB 241104A: SVOM/VT optical candidate
  46. GRB 241104A/EP241104a: Optical upper limits with Kinder observations
  47. GRB 241010A: host galaxy redshift z = 0.977
  48. EP241101a NUTTelA-TAO / BSTI Measurements 2024-11-02
  49. GRB 240821A: further radio observations with the VLA
  50. Fermi GRB 241104A: Global MASTER-Net observations report
  51. EP241101a: EP-FXT observations update
  52. EP241103a: GIT optical upper limit
  53. EP241021a: OHP/T193 further optical observations
  54. Fermi trigger No 752365806: Global MASTER-Net observations report
  55. LIGO/Virgo/KAGRA S241102br: OHP/T193 optical observations
  56. EP241103a: GOTO optical upper limit
  57. EP241101a: Possible detection of an optical counterpart with FTW
  58. EP241103a: Swift XRT detection and improved X-ray position
  59. EP241021a: continued SOAR observations
  60. EP241101a: Optical upper limits with Kinder observations
  61. EP241101a: OHP/T193 optical observations
  62. EP241103a: Gemini optical limits
  63. EP241103a: EP observation update
  64. LIGO/Virgo/KAGRA S241102br: MASTER observations and OT detection
  65. GRB 241030A: Swift-UVOT observations of the optical prompt flare
  66. EP241103a: GSP optical upper limit
  67. EP241103A: LCO optical observations
  68. EP241103a: Global MASTER-Net observations report
  69. EP241103a: an X-ray transient detected by Einstein Probe
  70. GRB 241030A: Rapid release of TESS data.
  71. EP241101a: Global MASTER-Net observations report
  72. LIGO/Virgo/KAGRA S241102br: NED Galaxies in the Localization Volume
  73. Kinder optical follow-up observations of EP241021a, EP241026b, and EP241030a/GRB241030A
  74. GRB241030A: OHP/T193 optical observations
  75. EP241101a: EP-WXT detection of a fast X-ray transient
  76. Swift GRB 241101A: Global MASTER-Net observations report
  77. GRB 241030A/EP241030a: TNOT observations of the optical counterpart
  78. EP241021a: Upper limit from Konus-Wind observations
  79. GRB 241030A: further SAO RAS optical observations
  80. GRB 241030A: Optical Observations via Virtual Telescope Project
  81. EP241021a: Liverpool Telescope optical follow-up observations
  82. GRB 241026A: SAO RAS optical observations
  83. GRB 241030B: NUTTelA-TAO / BSTI Optical Limits
  84. EP241021a: OHP/T193 optical observations
  85. GRB 241030A: Palomar 1-m telescope COSMOS optical observations
  86. GRB 241030B: Montarrenti Observatory optical upper limit
  87. GRB 241030A / EP241030a: FTW Optical and NIR observations of the optical counterpart
  88. Fermi trigger No 752083996: Global MASTER-Net observations report
  89. GRB 241030A: SAO RAS optical observations
  90. EP241021a: AMI-LA radio detection
  91. GRB 241029A: COLIBRI Detection of the Optical Counterpart
  92. GRB 241030B: Swift/UVOT Detection
  93. EP EP241030a: Global MASTER-Net observations report
  94. GRB 241029A: LCO optical detection
  95. Fermi trigger No 752006065: Global MASTER-Net observations report
  96. Swift GRB241030.77: Global MASTER-Net observations report
  97. GRB 241030A: COLIBRI Continuing Detection of the Afterglow
  98. GRB 241030B: SVOM/VT optical afterglow observations
  99. GRB 241030B: BTA observations
  100. GRB 241029A: SVOM/VT optical afterglow observations

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