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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"

5833 results found.

  1. LIGO/Virgo G298048: Subaru HSC follow-up observations
  2. LIGO/VIRGO G298048: Magellan Optical Spectrum of the Potential Optical Counterpart Associated with NGC 4993
  3. LIGO/Virgo G298048: VLA Detection
  4. LIGO/Virgo G298048: Optical Candidate Shows No Evidence for Previous Activity in Archival SkyMapper Transient Survey Data
  5. LIGO/Virgo G298048: Optical Candidate Shows No Evidence for Previous Activity in Archival ASAS-SN Data
  6. LIGO/Virgo G298048: DLT40 optical candidate
  7. LIGO/Virgo G298048: Potential optical counterpart discovered by Swope telescope
  8. LIGO/Virgo G297595: MASTER MASTER Bright PSN detection in error-box
  9. LIGO/Virgo G297595: INAF VST-ESO PARANAL observations
  10. LIGO/Virgo G297595: Subaru Hyper Suprime-Cam follow-up observations
  11. LIGO/Virgo G296853: Pierre Auger Observatory neutrino follow-up
  12. GRB 170810A: AbAO optical upper limit
  13. LIGO/Virgo G296853: Insight-HXMT observations
  14. LIGO/Virgo G296853 : MAXI/GSC observations
  15. GRB 170810A: Swift detection of a burst with a bright optical counterpart
  16. LIGO/Virgo G296853: Super-AGILE observations
  17. LIGO/Virgo G296853: no INTEGRAL data at the time of the event
  18. LIGO/Virgo G296853: Fermi-LAT search for high-energy gamma-ray counterpart
  19. LIGO/Virgo G296853: AGILE GRID observations
  20. LIGO/Virgo G296853: MASTER follow up observations
  21. LIGO/Virgo G296853: AGILE MCAL observations
  22. LIGO/Virgo G296853: Identification of a GW Binary Merger Candidate
  23. GRB 170808B: Fermi GBM observation
  24. GRB 170807A: Swift detection of a burst
  25. GRB 170728B: TShAO, SAO RAS and AbAO optical observations
  26. GRB170730A detecetd by INTEGRAL. Refined analysis
  27. IBAS weak Alert nr.7881: possible GRB 170730A
  28. GRB 170728A: Swift detection of a burst
  29. GRB 170724A: Swift detection of a burst
  30. Fermi GBM Detection of possible burst from AXP 4U 0142+61
  31. GRB 170710A: Swift detection of a burst
  32. GRB 170705A: Swift detection of a burst with an optical counterpart
  33. Konus-Wind observation of GRB 170626A
  34. GRB 170626A: Fermi GBM observation
  35. GRB 170626A: Swift detection of a burst
  36. IPN Triangulation of GRB 170616A (short/hard)
  37. LIGO/Virgo G288732: HAWC follow-up
  38. GRB 170610A: MAXI/GSC detection
  39. IPN Triangulation of GRB 170607B
  40. LIGO/Virgo G288732: GWFUNC/NOWT observations of the skymap and follow-up of the Fermi/LAT candidate
  41. GRB 170607A: Swift/UVOT Detection
  42. GRB 170607A: Swift detection of a burst with a bright optical counterpart
  43. GRB 170531A: MASTER Net job
  44. GRB 170531B: MASTER Net optical counterpart refind position and magnitude
  45. GRB 170531B: Redshift from GTC/OSIRIS
  46. GRB 170531B: MASTER Net OT detection
  47. GRB 170531B: Swift detection of a burst
  48. GRB 170531A: Swift detection of a burst
  49. LIGO/Virgo G268556: optical observations and classification of Pan-STARRS1 transients
  50. GRB 170522A: Swift-XRT observations
  51. GRB 170522A: Global MASTER-Net job
  52. GRB 170519A: Swift detection of a burst with an optical counterpart
  53. LIGO/Virgo G277583: UH88/SNIFS classification of ATLAS and PS1 transients
  54. Swift Trigger AXP CXOU J164710.2-455216: MASTER-OAFA observations
  55. Swift Trigger on AXP CXOU J164710.2-455216
  56. LIGO/Virgo G284239:SVOM/Mini-GWAC observations of the initial skymap
  57. GRB 170428A CALET Gamma-Ray Burst Monitor detection
  58. Short GRB 170428A: MASTER-OAFA final reduction of the optical observations
  59. GRB 170428A: GROND detection of the afterglow
  60. Konus-Wind observation of GRB 170428A
  61. GRB 170428A: MASTER-OAFA early optical observations
  62. GRB 170428A: Swift detection of a short burst
  63. Swift Trigger 748858: MASTER-OAFA early optical observations
  64. GRB 170409A: Fermi GBM Observation
  65. Swift triggered on SAX J1806.5-221
  66. IceCube-170321A: Swift-XRT observations
  67. LIGO/Virgo G275697: LOFAR follow-up
  68. Konus-Wind observation of GRB 170329A
  69. GRB 170329A: AstroSat CZTI detection
  70. GRB 170329A: Fermi GBM detection
  71. GRB 170329A: Fermi-LAT detection
  72. LIGO/Virgo G277583: INTEGRAL search for an X-ray and gamma-ray counterpart
  73. GRB 170317A: POLAR observation
  74. GRB 170317A: MITSuME Okayama Ks-band upper-limit
  75. GRB 170317A: Swift detection of a burst with an optical counterpart
  76. LIGO/Virgo G277583: ATLAS coverage and transients over the first 2 days
  77. LIGO/Virgo G277583: ERRATUM LV GCN 20871: TAROT Calern (TCA) observations
  78. LIGO/Virgo G277583: TAROT Calern (TCA) observations
  79. LIGO/Virgo G277583: SVOM/Mini-GWAC observations of the initial skymap
  80. LIGO/Virgo G270580: optical observations and classification of PS and MASTER sources
  81. GRB 170311A: GROND upper limits
  82. GRB 170311A: MASTER-OAFA early optical observations
  83. GRB 170306A: GROND afterglow detection
  84. GRB 170305A: POLAR observation
  85. LIGO/Virgo G275404 and AGL J1914+1043: INTEGRAL follow-up
  86. IPN Triangulation of GRB 170305A (short)
  87. GRB170305A: Fermi GBM detection
  88. LIGO/Virgo G275697: Additional iPTF Optical Transient Candidates
  89. LIGO/Virgo G275697: SVOM/Mini-GWAC observations of the initial skymap
  90. LIGO/Virgo G275697: iPTF Optical Transient Candidates
  91. LIGO/Virgo G275404: iPTF Optical Transient Candidates
  92. LIGO/Virgo G275404: Nearby galaxy observations by J-GEM collaboration
  93. LIGO/Virgo G275697: INTEGRAL search for a prompt gamma-ray counterpart
  94. LIGO/Virgo G275404: SVOM/Mini-GWAC: Observations of initial skymap
  95. IPN Triangulation of GRB 170222A (short/hard)
  96. LIGO/Virgo G274296: J-GEM optical/NIR follow-up observations
  97. LIGO/Virgo G274296: iPTF Optical Transient Candidates
  98. LIGO/Virgo G274296: Asiago 1.82m Optical Observations
  99. LIGO/Virgo G274296: PESSTO classification of 9 Pan-STARRS transients
  100. LIGO/Virgo G274296: Pan-STARRS imaging and discovery of 70 transients

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