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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"

16161 results found.

  1. EP240708a: GSP optical upper limit
  2. EP240708a: KAIT optical upper limit
  3. EP240708a: NOT optical observations
  4. EP240708a: SVOM/C-GFT optical upper limit
  5. EP240708a: Optical upper limits with Kinder observations
  6. EP240703b: GSP optical upper limit
  7. EP240703b: TRT optical upper limits
  8. EP240703a: TRT further optical observation
  9. EP240702a: TRT optical upper limits
  10. EP240703a: KAIT optical upper limit
  11. EP240703c: Kinder optical follow-up and Swift XRT observations
  12. EP240703a: BOOTES-3 optical upper limit
  13. EP240703a: Liverpool Telescope optical follow-up observations
  14. EP240703a/GRB 240703A: TRT optical candidate likely not real
  15. EP240703a: Kinder optical follow-up observations
  16. EP240703a/GRB 240703A: TRT and JinShan decaying optical afterglow candidate
  17. GRB 240619A: Host galaxy redshift from VLT/X-shooter
  18. EP240702a: GSP optical upper limit
  19. EP240626a: Montarrenti Observatory optical upper limit
  20. EP240626a: KAIT optical upper limit
  21. EP240625a: GRANDMA Optical Upper Limits
  22. EP240626a: BOOTES-7 optical upper limit
  23. EP240625a: NOT optical counterpart candidate
  24. GRB240615A: Gemini-North observations of the BAT and XRT positions
  25. GRB240615A: Gemini-North observations of the BAT and XRT positions
  26. EP240618a: NOT further optical observations
  27. EP240618a: NOT optical counterpart candidate
  28. GRB 240529A: JinShan optical observations
  29. EP240618a: GSP optical upper limit
  30. GRB 240619A: Fermi GBM Observation
  31. GRB 240619A: GOTO candidate optical afterglow
  32. EP240618a: Abastumani optical observationsEP240618a
  33. GRB 240615A: NOT optical observations
  34. EP240618a: GRANDMA Optical Upper Limits
  35. EP240618a: TRT optical upper limit
  36. EP240617a: STEP/T80S optical limits
  37. GRB 240615A: possible transient detection from Wendelstein observations
  38. EP240618a: BOOTES-6/DPRT optical upper limit
  39. GRB240615A: 1.3m DFOT optical upper limit
  40. EP240617a: BOOTES-6/DPRT optical upper limit
  41. X-ray transient EP240414a: Chandra late time observation
  42. GRB 240615A: FLWO-1.2m optical upper limits
  43. GRB 240615A: GOTO optical upper limits
  44. GRB 240529A: LBT optical detection and late temporal decay
  45. GRB 240529A : MITSuME Akeno optical afterglow detection
  46. GRB 240607A: Fermi GBM detection of a very bright burst
  47. GRB 240529A: SAO RAS optical observations
  48. Swift Trigger 1232755: likely consistent with noise and not astrophysical
  49. GRB 240529A: MASTER prompt OT detection
  50. GRB 240529A: continued SAO RAS optical observations
  51. GRB 240529A: OSN optical detection
  52. GRB 240529A: further SAO RAS optical observations
  53. GRB 240529A: AKO Optical Afterglow Follow-Up Observations
  54. LXT 240528A: GSP optical upper limit
  55. GRB 240529A: 1.3m DFOT Optical observations
  56. GRB 240529A : Mondy optical observations
  57. GRB 240529A: SAO RAS optical observations
  58. GRB 240529A: MAAO 0.7m telescope optical afterglow detection
  59. GRB 240529A: optical photometry from Konkoly
  60. GRB 240529A: GROWTH-India optical follow-up
  61. GRB 240529A: AKO Optical Afterglow Detection
  62. GRB 240529A: Skynet Optical Observations
  63. LIGO/Virgo S240527fv: GRANDMA/FRAM-Auger Optical Observations
  64. GRB240529A: BOOTES-6/DPRT optical detection
  65. GRB 240529A: NOT optical observations
  66. GRB 240529A: GOTO optical afterglow detection
  67. GRB 240529A: Swift detection of a burst with an optical counterpart
  68. EP240518a: GSP optical upper limit
  69. GRB 240516A: Swift/UVOT Upper Limits
  70. GRB 240516A ATCA radio observations
  71. IPN triangulation of GRB 240514B (short)
  72. GRB 240514E: A possible candidate BD-21 1074
  73. GRB 240502C: Zeiss-1000 at Koshka observations of GOTO24bao optical counterpart candidate
  74. GRB 240516A: GOTO optical upper limit
  75. GRB 240514B: AT2024ixa/GOTO24bph is not consistent with the Fermi localisation
  76. GRB 240514B: GOTO candidate optical counterpart
  77. transient: Xinglong Nearby Galaxy Supernova Survey detection of AT2024iss
  78. GRB 240511A: J-band observations with WINTER
  79. GRB 240511A : MITSuME Akeno optical upper limits
  80. GRB 240511A: optical afterglow detection from the NOT
  81. EP240506a: Xinglong optical upper limit
  82. EP240506a: CrAO ZTSH optical upper limit
  83. EP240506a: Archival radio searching
  84. EP240506a: TRT optical upper limit
  85. EP240506a: BOOTES Network optical upper limit
  86. EP240506a: Optical upper limit with Kinder observations
  87. GRB 240502A: 1.3m DFOT Optical upper limit
  88. LIGO/Virgo/KAGRA S240422ed: Additional WINTER near-infrared J-band observations
  89. LIGO/Virgo/KAGRA S240422ed: Swope Follow-up of AT2024hfr and AT2024hfs
  90. IceCube-240424A: GRANDMA Optical Upper Limit of Fermi J2151.3+0220
  91. GRB 240502C: Zeiss-1000 at Koshka observatory observations of GOTO optical counterpart candidates
  92. GRB 240502A: GOTO optical upper limit
  93. GRB 240415A 1.3m DFOT Optical upper limit
  94. GRB 240502C: GOTO possible optical counterpart candidates
  95. X-ray transient EP240414a: Detection of associated supernova
  96. LIGO/Virgo/KAGRA S240422ed: GECKO/7DT ToO observations
  97. LIGO/Virgo/KAGRA S240422ed: DDOTI Optical Upper Limit for J-GEM24a
  98. EP240426b: AST3-2 optical upper limit
  99. LIGO/Virgo/KAGRA S240422ed: Observations with 1.6m Mephisto
  100. LIGO/Virgo/KAGRA S240422ed: NOT optical observations of EP240426a

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