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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"

3360 results found.

  1. GRB 231115A: optical observations from INAF observatories
  2. GRB 231110A: Terskol Zeiss-2000 optical upper limit
  3. Swift GRB231110.89: Global MASTER-Net observations report
  4. Fermi GRB 231108A: Global MASTER-Net observations report
  5. Fermi trigger No 721006392: Global MASTER-Net observations report
  6. Fermi GRB 231106A: Global MASTER-Net observations report
  7. Fermi GRB 231103A: Global MASTER-Net observations report
  8. GRB 231104A: Fermi-LAT detection
  9. GRB 231104A: Swift detection of a bright burst
  10. GRB 231104A: Fermi GBM Final Real-time Localization
  11. Fermi trigger No 720498201: Global MASTER-Net observations report
  12. GRB 231028B: VZLUSAT-2 detection
  13. Fermi GRB 231030B: Global MASTER-Net observations report
  14. IceCube-231027A: Upper limits from a search for additional neutrino events in IceCube
  15. GRB 231028A: CALET Gamma-Ray Burst Monitor detection
  16. LIGO/Virgo/KAGRA S231029ai: Global MASTER-Net observations report
  17. GRB 231028A: AstroSat CZTI detection
  18. GRB 231028A: Glowbug gamma-ray detection
  19. GRB 231028A: Fermi GBM Detection
  20. Fermi trigger No 720224759: Global MASTER-Net observations report
  21. Swift GRB 231028A: Global MASTER-Net observations report
  22. LIGO/Virgo/KAGRA S231028bg: Identification of a GW compact binary merger candidate
  23. GRB 231028A: Fermi GBM Final Real-time Localization
  24. IceCube Alert 231027.18: Global MASTER-Net observations report
  25. LIGO/Virgo/KAGRA S231025t: Global MASTER-Net observations report
  26. LIGO/Virgo/KAGRA S231025a: Global MASTER-Net observations report
  27. Fermi trigger No 719846439: Global MASTER-Net observations report
  28. Fermi GRB 231019A: Global MASTER-Net observations report
  29. Konus-Wind detection of GRB 231018A
  30. IPN triangulation of GRB 231018A
  31. GRB 231018A: GROWTH-India Follow-Up of a Fermi Long GRB
  32. IceCube-231004A: No significant detection in HAWC
  33. LIGO/Virgo/KAGRA S231005j: Identification of a GW compact binary merger candidate
  34. NuEm-230927A: Swift-XRT follow-up
  35. LIGO/Virgo/KAGRA S230928cb: Identification of a GW compact binary merger candidate
  36. LIGO/Virgo/KAGRA S230922g: DECam GW-MMADS candidates
  37. IPN triangulation of GRB 230919A (short)
  38. GRB 230916A: NuSTAR Discovery of Prompt Emission from a Potential GRB
  39. Fermi trigger No 716449174: Global MASTER-Net observations report
  40. Fermi trigger No 716145795: Global MASTER-Net observations report
  41. GRB 230205A: LBT spectroscopy of two host galaxy candidates
  42. Fermi GRB 230906A: Global MASTER-Net observations report
  43. GRB 230904C: Fermi GBM Final Localization
  44. Fermi trigger No 715429986: Global MASTER-Net observations report
  45. Fermi GRB 230903A: Global MASTER-Net observations report
  46. GRB 230828A: AstroSat CZTI detection
  47. GRB 230828A: GRBAlpha detection
  48. GRB 230827B / GRB 230827256: Fermi GBM Observation
  49. Fermi GRB 230827A: Global MASTER-Net observations report
  50. AT 2023qxj: ZTF discovery of the likely afterglow of Fermi GRB 230827256
  51. Swift J1727.8-1613 (GRB 230824A): Skynet Optical Observations
  52. Integral GRB230824.72: Global MASTER-Net observations report
  53. Swift GRB230821.64: Global MASTER-Net observations report
  54. Swift Triggers 1186280 and 1186291 are not GRBs
  55. GRB 230818A: SAO RAS 6-m telescope spectroscopy
  56. Fermi GRB 230818A: Global MASTER-Net observations report
  57. Swift GRB230818.98: Global MASTER-Net observations report
  58. Swift GRB230818.98: Global MASTER-Net OT detection
  59. Swift GRB230816.80: Global MASTER-Net observations report
  60. LAT GRB230812.79: Global MASTER-Net observations report
  61. Fermi trigger No 713525317: Global MASTER-Net observations report
  62. GRB 230812A: Fermi GBM Final Real-time Localization
  63. GRB 230805B : MITSuME Akeno optical upper limits
  64. transient SPT-SVJ025406.5-702837: ATCA follow-up observations
  65. Fermi trigger No 713134237: Global MASTER-Net observations report
  66. GRB 230803A: AstroSat CZTI detection
  67. IceCube-230724A: JCMT/SCUBA-2 submm observations
  68. IceCube-230707A: JCMT/SCUBA-2 submm observations
  69. GRB 230723A: Detection of candidate millimeter-band radiation by SPT-3G
  70. Fermi trigger No 712306969: Global MASTER-Net observations report
  71. IceCube-230727A: No candidates from the Zwicky Transient Facility
  72. IceCube-230727A: Upper limits from a search for additional neutrino events in IceCube
  73. GRB 230728A: BOOTES-1 optical upper limit
  74. GRB 230728A: Fermi GBM Observation
  75. GRB 230728A: LCOGT Optical Upper Limit
  76. GRB 230728A: NOT optical observations and possible host galaxy
  77. Swift GRB230728.12: Global MASTER-Net observations report
  78. Fermi GRB 230723A: Global MASTER-Net observations report
  79. IPN triangulation of GRB 230715D
  80. GRB 230709C: Fermi GBM Final Localization
  81. IceCube Alert 230707.71: Global MASTER-Net observations report
  82. LIGO/Virgo/KAGRA S230707ai: Identification of a GW compact binary merger candidate
  83. LIGO/Virgo/KAGRA low-significance gravitational wave candidate S230701z: one counterpart neutrino candidate from IceCube neutrino searches
  84. IPN triangulation of GRB 230625B (ultra-long)
  85. GRB 230625B: CALET Gamma-Ray Burst Monitor detection
  86. GRB 230625B: AstroSat CZTI detection
  87. Fermi GRB 230628D: Global MASTER-Net observations report
  88. LIGO/Virgo/KAGRA S230628ax: Identification of a GW compact binary merger candidate
  89. GRB 230628E: LCOGT Optical Upper Limit
  90. Swift GRB230628.93: Global MASTER-Net observations report
  91. GRB 230628D: BALROG localization (Fermi Trigger 709676556 / GRB 230628849)
  92. GRB 230628D: Fermi GBM Final Real-time Localization
  93. LIGO/Virgo/KAGRA low-significance gravitational wave candidate S230628aj: one counterpart neutrino candidate from IceCube neutrino searches
  94. GRB 230628C: Fermi GBM Final Real-time Localization
  95. GRB 230628A: Fermi GBM Final Localization
  96. LIGO/Virgo/KAGRA S230527c: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  97. GRB 230625B: Swift/BAT-GUANO detection of a long burst
  98. INTEGRAL upper limit on any GRB associated with ZTF23aaoohpy/AT2023lcr
  99. ATLAS23msn/ZTF23aaoohpy/AT2023lcr: Zeiss-1000 of Koshka observatory optical observations
  100. LIGO/Virgo S230620ad: Global MASTER-Net observations report

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