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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').

3392 results found.

  1. GRB 240502C: Zeiss-1000 at Koshka observatory observations of GOTO optical counterpart candidates
  2. GRB 240415A 1.3m DFOT Optical upper limit
  3. Fermi GRB 240502B: Global MASTER-Net observations report
  4. Fermi GRB 240502A: Global MASTER-Net observations report
  5. Fermi trigger No 736197684: Global MASTER-Net observations report
  6. LIGO/Virgo/KAGRA S240501an: Identification of a GW compact binary merger candidate
  7. GRB 240429A: Fermi GBM Final Real-time Localization
  8. LIGO/Virgo/KAGRA S240428dr: Identification of a GW compact binary merger candidate
  9. LIGO/Virgo S240422ed: Swift XRT observation of EP240426a
  10. LIGO/Virgo/KAGRA S240422ed: NOT optical observations of EP240426a
  11. LIGO/Virgo/KAGRA S240422ed: Continued Magellan Observations
  12. LIGO/Virgo/KAGRA S240422ed: EP-FXT detection of a candidate counterpart EP240426a
  13. S240422ed: BlackGEM/MeerLICHT transient detection AT2024hgl/MLTJ080628.10-250116.4
  14. LIGO/Virgo/KAGRA S240422ed: Further near-infrared observations with Subaru/MOIRCS by J-GEM Collaboration
  15. LIGO/Virgo/KAGRA S240422ed: X-ray Upper Limits from EP-FXT for the Potential Electromagnetic Counterparts Reported by Swift and DECam
  16. LIGO/Virgo/KAGRA S240422ed: No significant candidates in GRANDMA/FRAM Observations
  17. LIGO/Virgo/KAGRA S240422ed: Subaru/MOIRCS near-infrared observations by J-GEM Collaboration
  18. LIGO/Virgo/KAGRA S240422ed: GW-MMADS DECam upper limits on the Swift/XRT source S240422ed_X61
  19. LIGO/Virgo/KAGRA S240422ed: AstroSat CZTI non-detection and upper limits
  20. Fermi trigger No 735470374: Global MASTER-Net observations report
  21. Fermi GRB 240421B: Global MASTER-Net observations report
  22. GRB 240421B: Fermi GBM Observation
  23. LIGO/Virgo/KAGRA S240421ar: Identification of a GW unmodeled transient candidate
  24. Fermi trigger No 735280430: Global MASTER-Net observations report
  25. GRB 240411A: GOTO early optical upper limits
  26. Fermi GRB 240417A: Global MASTER-Net observations report
  27. Fermi GRB 240415A: Global MASTER-Net observations report
  28. LIGO/Virgo/KAGRA S240413p: No Counterparts in DDOTI/OAN Optical Observations
  29. IPN triangulation of GRB 240410A
  30. IPN triangulation of GRB 240411A
  31. LIGO/Virgo/KAGRA S240413p: Global MASTER-Net observations report
  32. Fermi GRB 240407A: Global MASTER-Net observations report
  33. GRB 240402C: Glowbug gamma-ray detection
  34. GRB 240402C: GRBAlpha detection
  35. Fermi GRB 240402A: Global MASTER-Net observations report
  36. GRB 240329A: Glowbug gamma-ray detection
  37. GRB 240329A: AstroSat CZTI detection
  38. GRB 240329A: GRBAlpha detection
  39. Fermi trigger No 733366352: Global MASTER-Net observations report
  40. Fermi GRB 240329A: Global MASTER-Net observations report
  41. GRB 240329A: BALROG localization (Fermi Trigger 733441392 / GRB 240329905)
  42. GRB 240329A: Fermi GBM Final Real-time Localization
  43. Fermi GRB 240328B: Global MASTER-Net observations report
  44. Fermi GRB 240328A: Global MASTER-Net observations report
  45. GRB 240320A: Glowbug gamma-ray detection
  46. Konus-Wind detection of GRB 240315C (possible counterpart of EP240315a)
  47. Fermi trigger No 732657380: Global MASTER-Net observations report
  48. GRB 240320A: Fermi GBM Final Real-time Localization
  49. Fermi GRB 240318A: Global MASTER-Net observations report
  50. Fermi GRB 240317B: Global MASTER-Net observations report
  51. X-ray transient EP240315a: VLT/X-shooter spectroscopic redshift of z = 4.859
  52. Fermi trigger No 732299243: Global MASTER-Net observations report
  53. GRB 240315A: Fermi GBM Final Real-time Localization
  54. Fermi trigger No 731839490: Global MASTER-Net observations report
  55. Fermi GRB 240310A: Global MASTER-Net observations report
  56. GRB 240309A: MAXI/GSC detection
  57. GRID detection of GRB 240229A (Updated Report)
  58. GRID detection of GRB 240229A
  59. GRB 240229A: Glowbug gamma-ray detection
  60. GRB 240229A: GRBAlpha detection
  61. Fermi-LAT gamma-ray observations of IceCube-240229A
  62. GRB 240305C: AstroSat CZTI detection of a short burst
  63. GRB 240229A: VZLUSAT-2 detection
  64. Fermi trigger No 731161136: Global MASTER-Net observations report
  65. IceCube-240229A: Upper limits from a search for additional neutrino events in IceCube
  66. GRB 240229A: CALET Gamma-Ray Burst Monitor detection
  67. IceCube-240229A - IceCube observation of a high-energy neutrino candidate track-like event
  68. GRB 240225B: further SAO RAS optical observations
  69. Fermi GRB 240229A: Global MASTER-Net observations report
  70. IceCube Alert 240229.66: Global MASTER-Net observations report
  71. GRB 240229A: BALROG localization (Fermi Trigger 730908432 / GRB 240229588)
  72. GRB 240229A: Fermi GBM Final Real-time Localization
  73. GRB 240225B: VLT/X-shooter redshift
  74. GRB 240225B: 3.6m DOT observation
  75. GRB 240225B: MAXI/GSC detection
  76. Transient EPW20240219aa: Mondy optical observations
  77. Fermi trigger No 729914426: Global MASTER-Net observations report
  78. Gamma-ray flaring activity from the blazar 1ES 1959+650 observed by the Fermi-LAT
  79. Fermi trigger No 729650855: Global MASTER-Net observations report
  80. Fermi GRB 240213A: Global MASTER-Net observations report
  81. Fermi trigger No 729152364: Global MASTER-Net observations report
  82. Fermi trigger No 729012023: Global MASTER-Net observations report
  83. GRB 240204A: Mondy optical afterglow observations
  84. Fermi trigger No 728749569: Global MASTER-Net observations report
  85. GRB 240204A: optical afterglow detection with LCOGT 1m telescopes at Sutherland and Teide Observatories
  86. Fermi GRB 240204A: Global MASTER-Net observations report
  87. Fermi trigger No 728706420: Global MASTER-Net observations report
  88. IceCube Alert 240204.38: Global MASTER-Net observations report
  89. GRB 240129A: Fermi GBM Observation
  90. Fermi GRB 240127A: Global MASTER-Net observations report
  91. Konus-Wind detection of GRB 240119A (short/hard)
  92. IPN triangulation of GRB 240119A (short)
  93. GRB 240119A: GECAM detection of a short burst
  94. GRB 240119A: AstroSat CZTI detection of a short burst
  95. GRB 240118A: Mondy optical observations
  96. GRB 240119A: Fermi GBM Final Localization
  97. GRID detection of GRB 231230A
  98. IPN triangulation of GRB 240112A (long)
  99. GRB 240112C: Swift/UVOT Detection
  100. Fermi trigger No 726773850: Global MASTER-Net observations report

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