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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').

4003 results found.

  1. Fermi trigger No 736379109: Global MASTER-Net observations report
  2. GRB 240502C: GOTO possible optical counterpart candidates
  3. Fermi GRB 240502B: Global MASTER-Net observations report
  4. Fermi GRB 240502A: Global MASTER-Net observations report
  5. LIGO/Virgo/KAGRA S240422ed: GECKO/KMTNet Transient Candidates
  6. Fermi GRB 240501A: Global MASTER-Net observations report
  7. Fermi trigger No 736197684: Global MASTER-Net observations report
  8. GRB 240408B: VZLUSAT-2 detection
  9. LIGO/Virgo/KAGRA S240501an: Identification of a GW compact binary merger candidate
  10. LIGO/Virgo/KAGRA S240422ed: GRANDMA Optical Upper Limits for EP240426a
  11. LIGO/Virgo/KAGRA S240422ed: Continued Magellan Observations
  12. LIGO/Virgo/KAGRA S240426s: Identification of a GW compact binary merger candidate
  13. LIGO/Virgo/KAGRA S240422ed: Zwicky Transient Facility contuinued observations of S240422ed and candidate analysis
  14. S240422ed: MeerLICHT/BlackGEM photometry on AT2024hfx and archival ZTF detection
  15. LIGO/Virgo/KAGRA S240422ed: Further near-infrared observations with Subaru/MOIRCS by J-GEM Collaboration
  16. LIGO/Virgo/KAGRA S240422ed: Additional DECam GW-MMADS Candidates from the first two nights of observations
  17. LIGO/Virgo/KAGRA S240422ed: Archival BlackGEM/MeerLICHT detections of AT 2024hdr & AT 2024hdq
  18. LIGO/Virgo/KAGRA S240422ed: No significant counterpart candidates in HAWC observations
  19. LIGO/Virgo/KAGRA S240422ed: No significant candidates in GRANDMA/FRAM Observations
  20. LIGO/Virgo/KAGRA S240422ed: ATCA follow-up of candidate counterparts
  21. LIGO/Virgo S240422ed: Swift-XRT detection of 3 possible counterparts
  22. LIGO/Virgo/KAGRA S240422ed: DECam GW-MMADS Candidates
  23. IceCube Alert 240424.08: Global MASTER-Net observations report
  24. LIGO/Virgo/KAGRA S240422ed: SAGUARO upper limits from CSS
  25. LIGO/Virgo/KAGRA S240422ed: Subaru/MOIRCS near-infrared observations by J-GEM Collaboration
  26. LIGO/Virgo/KAGRA S240422ed: No Counterparts in DDOTI/OAN Optical Observations
  27. LIGO/Virgo/KAGRA S240422ed: Zwicky Transient Facility observations and candidates
  28. LIGO/Virgo/KAGRA S240422ed: GW-MMADS DECam observations
  29. LIGO/Virgo/KAGRA S240422ed: Magellan Observations
  30. LIGO/Virgo/KAGRA S240422ed: Updated NED Galaxies in the Localization Volume
  31. LIGO/Virgo/Kagra S240422ed: NED Galaxies in the Localization Volume
  32. Fermi GRB 240422A: Global MASTER-Net observations report
  33. Fermi trigger No 735280430: Global MASTER-Net observations report
  34. Fermi trigger No 735089036: Global MASTER-Net observations report
  35. Fermi GRB 240417A: Global MASTER-Net observations report
  36. Improved IPN triangulation of GRB 240411A
  37. GRB 240415A: SAO RAS optical observations
  38. Fermi GRB 240415A: Global MASTER-Net observations report
  39. Fermi trigger No 734754044: Global MASTER-Net observations report
  40. IPN triangulation of GRB 240411A
  41. GRB 240414A : OHP/T193 redshift determination
  42. LIGO/Virgo/KAGRA S240413p: Global MASTER-Net observations report
  43. LIGO/Virgo/KAGRA S240413p: Zwicky Transient Facility observations
  44. LIGO/Virgo/Kagra S240413p: NED Galaxies in the Localization Volume
  45. IceCube Alert 240412.23: Global MASTER-Net observations report
  46. GRB 240408B: GRBAlpha detection
  47. EP240408A: MASTER optical observations
  48. Swift Trigger 1220736: detection of 4U 1543-62.
  49. Fermi GRB 240408A: Global MASTER-Net observations report
  50. Fermi GRB 240407A: Global MASTER-Net observations report
  51. Fermi-LAT gamma-ray observations of IceCube-240327B
  52. Fermi-LAT gamma-ray observations of IceCube-240327A
  53. GRB 240331A: GRBAlpha detection
  54. GRB 240403B: Glowbug gamma-ray detection
  55. GRB 240403A: Glowbug gamma-ray detection
  56. IceCube-240327B: GRANDMA observations of 4FGL J0555.9+0030
  57. GRB 240403A: Fermi GBM Detection
  58. LXT 240402A: MASTER optical observations with AGN in error-box
  59. GRB 240402B: GWAC-F50A optical upper limit
  60. GRB 240403A: BALROG localization (Fermi Trigger 733838255 / GRB 240403498)
  61. Fermi trigger No 733808041: Global MASTER-Net observations report
  62. Fermi GRB 240402A: Global MASTER-Net observations report
  63. X-ray transient EP240331A: GRANDMA-Kilonova catcher optical upper limit
  64. EP240331A: MASTER optical observations
  65. Transient EP240315a: J-band observations of AT2024eju with WIRC
  66. IceCube-240327B: Upper limits from a search for additional neutrino events in IceCube
  67. IceCube-240327A: Upper limits from a search for additional neutrino events in IceCube
  68. GRB 240329A: Glowbug gamma-ray detection
  69. GRB 240324A: AstroSat CZTI detection of a short burst
  70. GRB 240331A: AstroSat CZTI detection
  71. GRB 240329A: AstroSat CZTI detection
  72. GRB 240329A: GRBAlpha detection
  73. Fermi trigger No 733366352: Global MASTER-Net observations report
  74. Fermi GRB 240329A: Global MASTER-Net observations report
  75. Fermi GRB 240328B: Global MASTER-Net observations report
  76. Fermi GRB 240328A: Global MASTER-Net observations report
  77. X-ray transient EP240315a: continued ATCA monitoring
  78. IceCube-240327B: No candidates from the Zwicky Transient Facility
  79. GRB 240328C: Glowbug gamma-ray detection
  80. IceCube Alert 240327.68: Global MASTER-Net observations report
  81. IceCube-240327B - IceCube observation of a high-energy neutrino candidate track-like event
  82. IceCube-240327A - IceCube observation of a high-energy neutrino candidate track-like event
  83. Fermi trigger No 733097506: Global MASTER-Net observations report
  84. X-ray transient EP240315a: Ondrejov D50 optical limit
  85. Fermi trigger No 733092476: Global MASTER-Net observations report
  86. GRB 240320A: Glowbug gamma-ray detection
  87. Fermi trigger No 732937833: Global MASTER-Net observations report
  88. Fermi GRB 240320A: Global MASTER-Net observations report
  89. GRB 240315C / X-ray transient EP240315a: Swift/BAT detection
  90. Fermi trigger No 732657380: Global MASTER-Net observations report
  91. GRB 240318A: Swift/BAT-GUANO detection of a burst outside the coded FOV
  92. X-ray transient EP240315a: ATCA detection of radio counterpart
  93. GRB 240318A: Glowbug gamma-ray detection
  94. GRB 240317C: Glowbug gamma-ray detection
  95. GRB 240318B: Glowbug gamma-ray detection
  96. X-ray transient EP240315a: PRIME near infrared detection
  97. X-ray transient EP240315a: 3.6 m TNG NIR detection
  98. X-ray transient EP240315a/AT2024eju: TShAO (Zeiss-1000) observatory optical upper limit
  99. X-ray transient EP240315a: EP-FXT detection of the X-ray afterglow
  100. Fermi GRB 240318A: Global MASTER-Net observations report

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