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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"

20968 results found.

  1. LIGO/Virgo/KAGRA S241109bn: Upper limits from EP-WXT observations
  2. Fermi trigger No 752878030: Global MASTER-Net observations report
  3. Integral GRB241109.89: Global MASTER-Net observations report
  4. LIGO/Virgo/KAGRA S241109bn: Coverage and upper limits from MAXI/GSC observations
  5. EP241109a: KAIT photometry and 3 m Shane spectroscopy from Lick observatory
  6. LIGO/Virgo/KAGRA S241109bn: Upper limits from Fermi-GBM Observations
  7. LIGO/Virgo/KAGRA S241109bn: Global MASTER-Net observations report
  8. EP241109a: confirmation of a stellar flare by BOOTES-7
  9. EP241109a: EP on-board trigger and autonomous follow-up observation
  10. GRB 241108A: Swift-XRT observations
  11. EP241107A: MASTER optical observations of xray transient
  12. EP241107a: KAIT optical observations
  13. GRB 241108A: Swift ToO observations
  14. GRB 241030A: TESS observations
  15. EP241107a: Kinder optical follow-up observations
  16. GRB 241025A: radio detection with the VLA
  17. EP241107a: AKO Optical Afterglow Follow-Up Observations
  18. EP241107a: GSP detects optical counterpart
  19. GRB 241105A: EP-FXT follow-up observations
  20. EP241107a: OHP/T193 photometric and spectroscopic observations
  21. GRB 241105a: PRIME near-infrared upper limits
  22. EP241107a: FTW Optical and NIR observations of the optical counterpart
  23. GRB 241105A: ePESSTO+ NTT optical afterglow detection
  24. EP241107a: GIT optical observations
  25. EP241107a: Global MASTER-Net observations report
  26. EP241107a: SVOM/C-GFT optical observations
  27. GRB 241025A: LBT optical observations
  28. GRB241105A: Gemini-South Optical Afterglow Detection
  29. EP241107a: EP on-board trigger and autonomous follow-up observation
  30. GRB 241105A: VLT/FORS2 optical afterglow rapid fading
  31. GRB 241105A: Swift/UVOT Detection
  32. EP241101a: CrAO ZTSH optical observations
  33. GRB 241030A: optical afterglow detection from the INAF Asiago Observatory
  34. GRB 241105A: BOOTES-7 optical detection
  35. GRB 241030A: Mondy optical observations
  36. GRB 241105A: SVOM/VT optical afterglow observations
  37. GRB 241105A: Swift-XRT afterglow detection
  38. GRB 241104A: Swift-XRT observations
  39. GRB 240511A: LCO upper limits
  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 241104A/EP241104a: Optical upper limits with Kinder observations
  48. GRB 241010A: host galaxy redshift z = 0.977
  49. EP241101a NUTTelA-TAO / BSTI Measurements 2024-11-02
  50. GRB 240821A: further radio observations with the VLA
  51. Fermi GRB 241104A: Global MASTER-Net observations report
  52. EP241101a: EP-FXT observations update
  53. EP241103a: GIT optical upper limit
  54. EP241021a: OHP/T193 further optical observations
  55. Fermi trigger No 752365806: Global MASTER-Net observations report
  56. LIGO/Virgo/KAGRA S241102br: OHP/T193 optical observations
  57. EP241103a: GOTO optical upper limit
  58. EP241101a: Possible detection of an optical counterpart with FTW
  59. EP241103a: Swift XRT detection and improved X-ray position
  60. EP241021a: continued SOAR observations
  61. EP241101a: Optical upper limits with Kinder observations
  62. EP241101a: OHP/T193 optical observations
  63. EP241103a: Gemini optical limits
  64. EP241103a: EP observation update
  65. LIGO/Virgo/KAGRA S241102br: MASTER observations and OT detection
  66. GRB 241030A: Swift-UVOT observations of the optical prompt flare
  67. EP241103a: GSP optical upper limit
  68. EP241103A: LCO optical observations
  69. EP241103a: Global MASTER-Net observations report
  70. EP241103a: an X-ray transient detected by Einstein Probe
  71. GRB 241030A: Rapid release of TESS data.
  72. EP241101a: Global MASTER-Net observations report
  73. LIGO/Virgo/KAGRA S241102br: NED Galaxies in the Localization Volume
  74. Kinder optical follow-up observations of EP241021a, EP241026b, and EP241030a/GRB241030A
  75. GRB241030A: OHP/T193 optical observations
  76. EP241101a: EP-WXT detection of a fast X-ray transient
  77. Swift GRB 241101A: Global MASTER-Net observations report
  78. GRB 241030A/EP241030a: TNOT observations of the optical counterpart
  79. EP241021a: Upper limit from Konus-Wind observations
  80. GRB 241030A: further SAO RAS optical observations
  81. GRB 241030A: Optical Observations via Virtual Telescope Project
  82. EP241021a: Liverpool Telescope optical follow-up observations
  83. GRB 241026A: SAO RAS optical observations
  84. GRB 241030B: NUTTelA-TAO / BSTI Optical Limits
  85. EP241021a: OHP/T193 optical observations
  86. GRB 241030A: Palomar 1-m telescope COSMOS optical observations
  87. GRB 241030B: Montarrenti Observatory optical upper limit
  88. GRB 241030A / EP241030a: FTW Optical and NIR observations of the optical counterpart
  89. Fermi trigger No 752083996: Global MASTER-Net observations report
  90. GRB 241030A: SAO RAS optical observations
  91. EP241021a: AMI-LA radio detection
  92. GRB 241029A: COLIBRI Detection of the Optical Counterpart
  93. GRB 241030B: Swift/UVOT Detection
  94. EP EP241030a: Global MASTER-Net observations report
  95. GRB 241029A: LCO optical detection
  96. Fermi trigger No 752006065: Global MASTER-Net observations report
  97. Swift GRB241030.77: Global MASTER-Net observations report
  98. GRB 241030A: COLIBRI Continuing Detection of the Afterglow
  99. GRB 241030B: SVOM/VT optical afterglow observations
  100. GRB 241030B: BTA observations

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