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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"

15722 results found.

  1. GRB 241127A: SVOM/GRM observation
  2. GRB 241127A: LCOGT (40-cm) optical counterpart detection
  3. Swift GRB241127.91: Global MASTER-Net OT detection
  4. EP241126a: WFST Observations
  5. GRB 241127A: Swift detection of a burst with an optical counterpart
  6. Swift GRB241127.91: Global MASTER-Net OT detection
  7. EP241126a: Optical Upper limits with Kinder observations
  8. EP trigger ID 01709122294: 1.6m Mephisto multi-band optical observations
  9. EP241126a: EP-FXT follow-up observation update
  10. EP241126a: GSP detects optical counterpart
  11. EP241126a: TRT optical counterpart detection
  12. LIGO/Virgo/KAGRA S241125n: COLIBRÍ Upper Limits on Optical Counterparts to Two of the Swift/XRT Sources
  13. GRB 241113B: EP-FXT afterglow detection
  14. LIGO/Virgo/KAGRA S241125n: DDOTI Optical Upper Limits
  15. LIGO/Virgo/KAGRA S241125n: Gaoyazi/GOT optical observations
  16. SVOM/GRM detection of a short burst from SGR 1830
  17. LIGO/VIRGO/KAGRA S241125n: GROWTH-India telescope optical observations
  18. GRB 241026A: radio detection with the VLA
  19. EP241125a: Optical upper limit with Kinder observations
  20. LIGO/Virgo/KAGRA S241125n: COLIBRÍ Upper Limits on a Optical Counterpart at the BAT Position
  21. LIGO/Virgo/KAGRA S241125n: Kinder optical upper limit in the BAT error region
  22. GRB 241113B: SVOM/VT optical afterglow observations
  23. GRB 241105A: ATCA radio detection
  24. GRB 241026A: VIRT Optical Upper Limit
  25. GRB 241025A: VIRT Optical Upper Limit
  26. GRB241120A: OHP/T193 optical observations
  27. EP241021a and EP241026b: Keck/LRIS spectroscopic observations
  28. EP trigger ID 01709065118: Keck/LRIS spectroscopic observations
  29. EP-WXT trigger 01709018832: Lick/Kast spectroscopy with the 3 m Shane telescope
  30. GRB 241120A: Mondy and AbAO optical observations
  31. EP241119a: Optical upper limits with Kinder observations
  32. EP241119a: GIT optical upper limits
  33. GRB 241113A: Possible ATCA Radio detection
  34. GRB 241112B: Mephisto further optical observations
  35. GRB 241117A: SVOM/GRM observation of a short burst with extended emission
  36. EP241115a/GRB 241115D: Optical upper limits with Kinder observations
  37. GRB 241115A: Mephisto upper limits
  38. GRB 241113B: Mephisto upper limits
  39. GRB 241115D / EP 241115a: SVOM/GRM observation
  40. GRB 241115A: LCOGT Optical Upper Limits
  41. EP 241113a: LBT possible optical counterpart
  42. GRB 241113B: KAIT Optical Afterglow Candidate
  43. GRB 241113A: J-band observations with WINTER
  44. GRB 241030A: LCO optical observation
  45. GRB 241113A: 1.6m Mephisto and 50cm array optical upper limits
  46. GRB 241113A: KAIT optical observations
  47. GRB 241113B: SVOM/GRM observation
  48. EP241107a: SOAR upper limits
  49. GRB 241113A: REM detection of the optical/NIR afterglow
  50. GRB 241113A: LCO optical observations
  51. GRB 241112B: GMG Optical Upper Limit
  52. GRB241113A: LCOGT (40-cm) optical counterpart detection
  53. GRB 241113A: MASTER010615.66-224018.2 optical counterpart detection
  54. GRB 241113A: Swift detection of a burst with an optical counterpart
  55. SVOM/GRM detection of a short burst from SGR 1E1841-045
  56. GRB 241105A: ATCA Radio Upper Limits
  57. GRB 241112B: AbAO optical upper limit
  58. GRB 241107A: GROWTH-India telescope optical upper limit
  59. GRB 241112B: Optical afterglow detection confirmation in revisiting the Mephisto data
  60. GRB 241112B: LCO optical detection of the SVOM/VT candidate
  61. GRB 241112B: SVOM/GRM observation
  62. GRB 241112B: SVOM/VT afterglow detection
  63. GRB 241112B: Mephisto optical upper limits
  64. GRB 241112B: GOTO optical upper limits
  65. GRB 241030B: TESS detection of optical counterpart
  66. EP241107a: AbAO optical upper limit
  67. GRB 241108A: Further COLIBRÍ Upper Limits on the Optical Counterpart
  68. EP241107A: MASTER optical observations of xray transient
  69. EP241107a: KAIT optical observations
  70. GRB 241030A: TESS observations
  71. GRB 241108A: COLIBRÍ Upper Limits on the Optical Counterpart
  72. EP241107a: Kinder optical follow-up observations
  73. GRB 241025A: radio detection with the VLA
  74. EP241107a: AKO Optical Afterglow Follow-Up Observations
  75. EP241107a: GSP detects optical counterpart
  76. EP241107a: Gemini-South spectroscopic confirmation (z = 0.456)
  77. GRB 241105A: EP-FXT follow-up observations
  78. EP241107a: FTW Optical and NIR observations of the optical counterpart
  79. GRB 241105A: ePESSTO+ NTT optical afterglow detection
  80. EP241107a: GIT optical observations
  81. EP241107a: SVOM/C-GFT optical observations
  82. EP241107a: AKO Optical Afterglow Detection
  83. GRB 241025A: LBT optical observations
  84. GRB241105A: Gemini-South Optical Afterglow Detection
  85. GRB 241105A: VLT/FORS2 optical afterglow rapid fading
  86. GRB 241105A: Swift/UVOT Detection
  87. EP241101a: CrAO ZTSH optical observations
  88. GRB 241030A: optical afterglow detection from the INAF Asiago Observatory
  89. GRB 241105A: BOOTES-7 optical detection
  90. GRB 241030A: Mondy optical observations
  91. GRB 241105A: Fermi GBM Observation of a Short Burst with Extended Emission
  92. GRB 241105A: SVOM/VT optical afterglow observations
  93. GRB 241105A: Swift-XRT afterglow detection
  94. GRB 241105A: VLT/FORS2 spectroscopic redshift z = 2.681
  95. GRB 240511A: LCO upper limits
  96. GRB 241105A: Swift/BAT-GUANO arcminute localization of a short burst
  97. GRB 241104A: NOT optical non-detection
  98. GRB 241105A: GOTO tentative optical counterpart candidate
  99. GRB 241104A: SVOM/VT optical candidate
  100. GRB 241104A/EP241104a: Optical upper limits with Kinder observations

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