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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"

45413 results found.

  1. GRB 260913A: SVOM trigger sb26091302 is not an astrophysical event
  2. GRB 260818A: Continued ATCA observations
  3. SVOM GRB260913.32: Global MASTER-Net observations report
  4. GRB 260913A: SVOM/C-GFT optical upper limit
  5. GRB 260913A: SVOM detection of a faint burst
  6. GRB 260909A: OSN 1.5m, CAHA 2.2m and GTC 10.4m optical upper limits
  7. GRB 260907A: SVOM/GRM observation
  8. GRB 260909A: CrAO and AbAO optical upper limits
  9. GRB 260909A: SVOM/ECLAIRs refined analysis
  10. GRB 260910B: GOTO tentative optical counterpart candidates
  11. GRB 260909A: Swift ToO observations
  12. GRB 260910B: Fermi GBM Final Real-time Localization
  13. GRB 260909A: KAIT optical upper limit
  14. GRB 260903A: Swift-XRT observations
  15. EP260806a: VLA+ALMA radio detections
  16. GRB 260909A: OHP/T193 z-band upper limit
  17. GRB 260909A: VLT optical and near-infrared upper limits
  18. EP Alert 260909.53: Global MASTER-Net observations report
  19. GRB 260909A: EP-FXT follow-up observation
  20. GRB 260910A: Fermi GBM Final Real-time Localization
  21. EP260806a: NOEMA detection
  22. EP260623a: NOEMA detections
  23. GRB 260909A: SVOM/VT optical upper limits
  24. GRB 260909A: SVOM/GRM observation
  25. GRB 260909A: Mondy optical observations and afterglow candidate
  26. GRB 260909A: Xinglong 2.16m optical upper limit
  27. GRB 260909A: SVOM/C-GFT optical upper limit
  28. GRB 260909A: SVOM detection of a burst
  29. The EP-WXT trigger 01709306297 is likely the known LMXB 4U 1745-203
  30. Fermi trigger No 810554827: Global MASTER-Net observations report
  31. EP Alert 260908.60: Global MASTER-Net observations report
  32. GRB 260907A: Glowbug gamma-ray detection of a likely short burst
  33. GRB 260903A: Swift ToO observations
  34. Fermi GRB 260907B: Global MASTER-Net observations report
  35. GRB 260903A: SAO RAS optical upper limit
  36. The EP-WXT trigger 01709305715 is likely a flaring star
  37. GRB 260907B: Fermi GBM Final Real-time Localization
  38. Fermi GRB 260907A: Global MASTER-Net observations report
  39. GRB 260907A: Fermi GBM Final Real-time Localization
  40. EP260903a: EP-FXT follow-up observation
  41. EP Alert 260905.11: Global MASTER-Net observations report
  42. The EP-WXT trigger 01709302592 is likely a flaring star
  43. GRB 260903A: J-band upper limit with WINTER
  44. EP Alert 260903.47: Global MASTER-Net observations report
  45. GRB 260903A: SVOM/ECLAIRs refined analysis
  46. GRB260903A: Liverpool Telescope optical observations
  47. GRB 260903A: SAO RAS optical observations
  48. GRB 260830A: GECAM-B detection of a burst
  49. EP260903a: EP-WXT detection of a fast X-ray transient
  50. EP Alert 260903.62: Global MASTER-Net observations report
  51. GRB 260830A: Insight-HXMT/HE detection
  52. GRB 260903A: EP-FXT follow-up observation
  53. GRB 260903A: OHP/T193 optical afterglow detection
  54. GRB 260903A: NOT optical observations and afterglow fading
  55. NuSTAR Transient 260828: SOAR Optical Upper Limits
  56. SVOM GRB260903A: Global MASTER-Net observations report
  57. GRB 260903A: LCO optical observations
  58. GRB 260903A: SVOM/VT optical candidate
  59. GRB 260903A: Retraction of optical counterpart of GCN 45501
  60. GRB 260831A: GECAM-B observation
  61. GRB 260903A: LCO optical counterpart detection
  62. GRB 260827A: Insight-HXMT/HE detection
  63. GRB 260903A: SVOM detection of a soft faint burst
  64. EP260901a: SVOM/VT optical upper limits
  65. EP260901a: EP-FXT follow-up observation
  66. Konus-Wind detection of GRB 260829A
  67. GRB 260829A: SVOM/GRM observation
  68. GRB 260818A: ATCA detection of a candidate radio counterpart
  69. EP260830a: EP-FXT follow-up observation
  70. EP260901a: Global MASTER-Net observations report
  71. IceCube-260827A: No transient candidates from the Zwicky Transient Facility
  72. GRB 260831B / sb26083106: SVOM/GWAC-F60A/B confirmation of optical variation of nova V* GK Per
  73. GRB 260831B / sb26083106: SVOM/VT optical variability of V* GK Per
  74. NuSTAR Transient 260828: LCO Optical Upper Limits
  75. EP260901a: EP-WXT detection of a fast X-ray transient
  76. SVOM trigger sb26083106 is not a GRB
  77. GRB 260829A: AstroSat CZTI detection
  78. GRB 260831B: EP-FXT follow-up observation
  79. GRB 260830A: NuSTAR detection of prompt emission
  80. GRB 260831B: LCO optical upper limits
  81. EP260830a: Global MASTER-Net observations report
  82. EP260830a: EP-WXT detection of a fast X-ray transient
  83. GRB 260827A: SVOM/GRM observation
  84. NuSTAR 260828: a 1100s hard X-ray transient
  85. GRB 260831B: SVOM detection of a possible burst
  86. IPN triangulation of GRB 260829A
  87. GRB 260827A: Glowbug gamma-ray detection
  88. EP260727a: ATCA 10 GHz detection
  89. GRB 260831A: Fermi GBM Final Real-time Localization
  90. Fermi-LAT Gamma-ray Observations of IceCube-260827A
  91. Fermi-LAT Gamma-ray Observations of IceCube-260825A
  92. GRB 260829A: GECAM-B observation of a long burst
  93. GRB 260825A: SVOM/GRM observation of a long burst
  94. GRB 260825A: GECAM-B observation
  95. GRB 260829A: Fermi GBM Detection
  96. GRB 260825A: AstroSat CZTI detection
  97. GRB 260829A: BALROG localization (Fermi Trigger 809676494 / GRB 260829256)
  98. GRB 260829A: Fermi GBM Final Real-time Localization
  99. IceCube-260827A: Upper limits from a search for additional neutrino events in IceCube
  100. IceCube-260825A: Upper limits from a search for additional neutrino events in IceCube

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