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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').

10636 results found.

  1. IceCube-250421A: Upper limits from a search for additional neutrino events in IceCube
  2. Konus-Wind detection of GRB 250424A
  3. Fermi-LAT gamma-ray observations of IceCube-250421A
  4. GRB 250424A: Kilonova-Catcher optical afterglow detection
  5. GRB 250404A / EP250404a: GRBAlpha detection
  6. GRB 250424A: Swift-XRT refined Analysis
  7. GRB 250424A: AstroSat CZTI detection of a bright long burst
  8. GRB 250424A: DDOTI Afterglow Detection
  9. LIGO/Virgo/KAGRA S250328ae: Subaru/PFS Spectroscopic Follow up and Candidates
  10. SVOM/sb25042207: BOOTES-2 early optical upper limit
  11. SVOM/sb25042207: GOTO optical upper limits
  12. GRB 250421A: AstroSat CZTI detection
  13. GRB 250419A: Mephisto Multi-band Optical Detection
  14. GRB 250419A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations.
  15. IC-250421A: LAST optical observations of the IceCube neutrino candidate
  16. GRB 250419A: Mondy Continued Optical Observations
  17. Fermi GRB 250421A: Global MASTER-Net observations report
  18. GRB 250421B: AstroSat CZTI detection of a bright long burst
  19. IceCube Alert 250421.71: Global MASTER-Net observations report
  20. GRB 250419A: Liverpool Telescope observations
  21. GRB 250419A: JinShan optical observations
  22. GRB 250416C / EP250416a: SVOM/GRM observation of a burst
  23. GRB 250419A: LCO optical afterglow multi-band observations
  24. GRB 250419A: MASTER optical afterglow observation
  25. Fermi-LAT Gamma-ray Observations of IceCube-250416A
  26. GRB 250419A: Swift-XRT refined Analysis
  27. Konus-Wind detection of GRB 250416C (a counterpart of EP250416a)
  28. EP250416a: refined EP-WXT and EP-FXT analysis
  29. Konus-Wind detection of GRB 250403A
  30. IceCube-250416A: DDOTI Optical Observations
  31. EP250416a: GSP optical upper limit
  32. EP250416a: Global MASTER-Net observations report
  33. EP250416a: Einstein Probe detection of an X-ray transient
  34. IceCube-250416A: Global MASTER-Net observations report
  35. GRB 250413A: AstroSat CZTI detection
  36. GRB 250412A: AstroSat CZTI detection
  37. EP250404a: Nanshan 0.43m Telescope optical observatios
  38. Fermi trigger No 766148493: Global MASTER-Net observations report
  39. Fermi trigger No 766173972: Global MASTER-Net observations report
  40. Fermi GRB 250411A: Global MASTER-Net observations report
  41. GRB 250320B: cubesat Avion detection
  42. Fermi-LAT gamma-ray observations of IceCube-250406A
  43. Konus-Wind detection of GRB 250407A
  44. GRB 250407A: EP-WXT afterglow detection
  45. GRB 250407A: COLIBRÍ/DDRAGO Detection of the Optical Counterpart
  46. GRB 250407A: Fermi GBM Detection
  47. GRB 250407A: Swift-XRT afterglow detection
  48. Fermi GRB 250407A: Global MASTER-Net observations report
  49. GRB 250407A: SRG/ART-XC afterglow detection
  50. LIGO/Virgo/KAGRA S250331o: Upper limits from Swift/BAT-GUANO
  51. Konus-Wind detection of GRB 250406B (short/hard)
  52. GRB 250406A: AstroSat CZTI detection
  53. Fermi trigger No 765663719: Global MASTER-Net observations report
  54. Fermi GRB 250406A: Global MASTER-Net observations report
  55. EP250404a / GRB 250404A: Montarrenti Observatory optical observations
  56. EP250404a / GRB 250404A: J band observations by SYSU 80cm telescope
  57. Konus-Wind detection of GRB 250404A / EP250404a
  58. EP250404a: refined analysis of the EP-WXT and EP-FXT observations
  59. GRB 250404A / EP250404a: Leavitt Observatory optical counterpart detection
  60. GRB 250404B: AstroSat CZTI detection of a short burst
  61. GRB 250403A: AstroSat CZTI detection
  62. EP250404a: Osservatorio Astronomico "Nastro Verde" optical observations: detection of an optical counterpart
  63. EP250404a: LCO optical counterpart detection
  64. Fermi GRB 250404A: Global MASTER-Net observations report
  65. EP250404a: Xinglong decaying optical counterpart
  66. EP250404a: Global MASTER-Net observations report
  67. EP250404a: AKO Optical Afterglow Detection
  68. EP250404a: LAST detection of optical counterpart
  69. GRB 250402A: Swift/BAT-GUANO localization skymap of a burst
  70. EP250404a: Mephisto multi-band optical detection
  71. EP250321A: J band upper limit by SYSU 80cm telescope
  72. EP250404a: BOOTES-4/JGT optical afterglow detection
  73. EP250404a: Nanshan/HMT optical counterpart detection
  74. EP250404a: Einstein Probe detection of an X-ray transient
  75. IceCube-250330A: MASTER detection of PKS 2032+107 blazar flare with Zhirkov effect
  76. GRB 250402A: EP-FXT afterglow detection
  77. GRB 250322A: 10 GHz VLA radio upper limits
  78. GRB 250403A: GOTO optical counterpart follow-up observations
  79. GRB 250403A : SVOM detection of a burst
  80. GRB 250402B: AstroSat CZTI detection of a short burst
  81. GRB 250331C: Calapai Observatory, Massa S. Giorgio (Messina), upper limit
  82. GRB 250331D: Fermi GBM observation
  83. GRB 250328A: AbAO AS-32 Optical Observations
  84. GRB 250322B: GRBAlpha detection
  85. LIGO/Virgo/KAGRA S250328ae: DECam DESGW Candidates (Epoch 2)
  86. Fermi GRB 250331D: Global MASTER-Net observations report
  87. GRB 250329A: AbAO, Mondy and SAO RAS optical upper limits
  88. Konus-Wind detection of GRB 250327B
  89. LIGO/Virgo/KAGRA S250331o: NED Galaxies in the 3-Initial Localization Volume
  90. LIGO/Virgo/KAGRA S250328ae: Swift XRT observations, 34 possible X-ray sources
  91. Fermi-LAT gamma-ray observations of IceCube-250330A
  92. GRB 250331A: MAXI/GSC detection
  93. Fermi GRB 250330B: Global MASTER-Net observations report
  94. IceCube Alert 250330.35: Global MASTER-Net observations report
  95. GRB 250329B: Swift-XRT afterglow detection
  96. Swift GRB250330.26: Global MASTER-Net observations report
  97. LIGO/Virgo/KAGRA S250328ae: DECam DESGW Candidates (Epoch 1)
  98. GRB 250329A: SVOM detection of a burst
  99. LIGO/Virgo/KAGRA S250328ae: NED Galaxies in the 4-Update Localization Volume
  100. EP250302a: SPI-ACS/INTEGRAL Upper Limit

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