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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"

5079 results found.

  1. Fermi trigger No 750211959: Global MASTER-Net observations report
  2. GRB 240821A: Host galaxy redshift from VLT/X-shooter
  3. IceCube Alert 241006.94: Global MASTER-Net observations report
  4. Fermi trigger No 749721670: Global MASTER-Net observations report
  5. Fermi trigger No 749630753: Global MASTER-Net observations report
  6. GRB 241001A : SVOM/VT optical detection
  7. GRB 241002B: GOTO24gpc/AT 2024xbg follow-up observations update
  8. NuEm-240926A: Upper limits from a search for coincident neutrino events in IceCube
  9. GRB 241002B: GOTO optical counterpart candidate
  10. GRB 241002A: 1.5m OSN optical upper limit
  11. LIGO/Virgo/KAGRA S241002e: Identification of a GW compact binary merger candidate
  12. EP EP240930a: Global MASTER-Net observations report
  13. LIGO/Virgo/KAGRA S240930aa: Identification of a GW compact binary merger candidate
  14. Fermi GRB 240929A: Global MASTER-Net observations report
  15. LIGO/Virgo/KAGRA S240924a: Identification of a GW compact binary merger candidate
  16. LIGO/Virgo S240919bn: GOTO optical upper limits
  17. EP240919a / GRB 240919A: KAIT optical upper limit
  18. EP240919a: GOTO optical upper limits
  19. EP EP240918a: Global MASTER-Net observations report
  20. GRB 240916A: NOT optical observation
  21. GRB 240913B: Fermi GBM Final Real-time Localization
  22. Fermi GRB 240913A: Global MASTER-Net observations report
  23. GRB 240913A: Fermi GBM Final Real-time Localization
  24. GRB 240905E: NUTTelA-TAO / BSTI Optical Limits
  25. GRB 240905E: CrAO Optical Afterglow observations, possible OT candidate
  26. GRB 240905E: Swift-XRT refined Analysis
  27. GRB 240905E: Swift detection of a burst
  28. GRB 240825A: MeerLICHT afterglow detection
  29. Fermi trigger No 746882332: Global MASTER-Net observations report
  30. Fermi trigger No 746587425: Global MASTER-Net observations report
  31. GRB 240828A: KAIT Optical Afterglow Candidate
  32. GRB 240825A: iTelescope optical observations
  33. GRB 240829A: Swift detection of a burst
  34. Swift GRB240829.16: Global MASTER-Net observations report
  35. LAT GRB240828.62: Global MASTER-Net observations report
  36. Fermi GRB 240828A: Global MASTER-Net observations report
  37. Fermi trigger No 746438824: Global MASTER-Net observations report
  38. GRB 240825A: ALMA detection
  39. GRB 240825A: SAO RAS optical observations
  40. GRB 240825A: VLT/X-shooter redshift
  41. GRB 240824A: KAIT optical upper limit
  42. GRB 240824A: Swift detection of a burst
  43. GRB 240821A: Swift-XRT observations
  44. Fermi GRB 240821A: Global MASTER-Net observations report
  45. Fermi trigger No 746019401: Global MASTER-Net observations report
  46. Fermi trigger No 745935375: Global MASTER-Net observations report
  47. Trigger 1249878: Swift detection of another burst from SGR 1E 1841-045 / Kes 73
  48. GRB 240819A: Swift-XRT observations
  49. EP240820a: TRT optical upper limit
  50. GRB 240819A: KAIT optical upper limit
  51. EP240816b: Liverpool Telescope optical follow-up observations
  52. GRB 240814A: Fermi GBM Final Real-time Localization
  53. LIGO/Virgo/KAGRA S240813c: Identification of a GW compact binary merger candidate
  54. GRB 240812D: Fermi GBM Final Real-time Localization
  55. EP240801a: Assy-Turgen optical observations
  56. Fermi trigger No 745057312: Global MASTER-Net observations report
  57. EP240807a: STEP/T80S optical limits
  58. EP EP240807a: Global MASTER-Net observations report
  59. EP EP240806a: Global MASTER-Net observations report
  60. GRB 240801A: GRBAlpha detection
  61. The EP-WXT trigger 01709018832 on August 7th is likely a flaring star
  62. Fermi trigger No 744629911: Global MASTER-Net observations report
  63. Improved IPN triangulation of GRB 240802A / EP 240802a
  64. GRB 240626B: VZLUSAT-2 detection
  65. Fermi trigger No 744544656: Global MASTER-Net observations report
  66. EP240801a: BTA BVRI photometry
  67. Fermi GRB 240805A: Global MASTER-Net observations report
  68. EP240801a: Continued optical observations at ZTSh (CraO)
  69. EP240804a: LCOGT optical counterpart detection
  70. Fermi GRB 240804A: Global MASTER-Net observations report
  71. EP240802a: Montarrenti Observatory optical upper limit
  72. EP240801a: Osservatorio Astronomico Nastro Verde upper limit
  73. Fermi trigger No 744278264: Global MASTER-Net observations report
  74. EP240801a: GRANDMA and Kilonova-Catcher optical observations
  75. EP240801a: Leavitt Observatory optical observations
  76. EP240801a: GMG observation
  77. EP240801a: EP-WXT detection and EP-FXT follow-up observation of a fast X-ray transient
  78. Fermi GRB 240801A: Global MASTER-Net observations report
  79. GRB 240801A: Fermi GBM Final Real-time Localization
  80. Fermi trigger No 744128417: Global MASTER-Net observations report
  81. Fermi GRB 240730B: Global MASTER-Net observations report
  82. Fermi trigger No 743953682: Global MASTER-Net observations report
  83. Fermi GRB 240727A: Global MASTER-Net observations report
  84. Fermi trigger No 743868421: Global MASTER-Net observations report
  85. GRB 240627A: GRBAlpha detection
  86. Fermi GRB 240726A: Global MASTER-Net observations report
  87. GRB240727A: Skynet Optical Afterglow Observations
  88. GRB 240727A: Swift detection of a burst
  89. IceCube-240725A: Upper limits from a search for additional neutrino events in IceCube
  90. IceCube Alert 240725.22: Global MASTER-Net observations report
  91. Fermi trigger No 743219692: Global MASTER-Net observations report
  92. Fermi GRB 240718A: Global MASTER-Net observations report
  93. LIGO/Virgo/KAGRA S240716b: Identification of a GW compact binary merger candidate
  94. GRB 240715A: Fermi GBM Final Real-time Localization
  95. EP240708a: GSP optical upper limit
  96. GRB 240712A: Swift detection of a burst
  97. Fermi trigger No 742405878: Global MASTER-Net observations report
  98. EP240708a: NOT optical observations
  99. EP240702a: TRT optical upper limits
  100. EP240703a: BTA observations

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