Skip to main content
Updates to LVK & CHIME Notices, Schema v7.2.3! See news and announcements

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"

2803 results found.

  1. IceCube-170922A - IceCube observation of a high-energy neutrino candidate event
  2. LIGO/Virgo G298048: SRT observations of SSS17a in NGC 4993
  3. LIGO/Virgo G299232: Lulin Observations of Possible OTs
  4. LIGO/VIRGO G298048: Radio detection of SSS17a at 6 GHz with the VLA
  5. GRB 170902A: Swift detection of a burst or possible Galactic transient
  6. LIGO/Virgo G298048
  7. LIGO/Virgo G298048: Possible Plateau in Ks band revealed by continued Gemini-South observations
  8. LIGO/Virgo G299232: HAWC follow-up
  9. LIGO/Virgo G298048: Zadko Telescope 7 day observations of the OT candidate SSS17a/DLT17ck
  10. GRB 170827A: Swift-XRT refined Analysis
  11. LIGO/Virgo G299232: OVRO-LWA simultaneous low frequency radio observations of localization region
  12. LIGO/Virgo G299232/PGWB170825.55: MASTER Global-Net OT inside NGC1343 discovery
  13. LIGO/Virgo G299232 : Fermi-LAT search for high-energy gamma-ray counterpart
  14. LIGO/Virgo G298389: HAWC follow-up
  15. LIGO/Virgo G299232: AGILE MCAL detection of a short gamma-ray candidate
  16. LIGO/Virgo G297595: INTEGRAL pointed follow-up observations
  17. LIGO/Virgo G298048: MASTER Global-Net early optical observations and the Possible KiloNova SSS17a in NGC 4993 photometry and merging rate
  18. LIGO/Virgo G298048: HAWC follow-up
  19. LIGO/Virgo G298048: H.E.S.S. very-high energy gamma-ray follow-up
  20. LIGO/Virgo G298048: INTEGRAL pointed follow-up observations
  21. LIGO/Virgo G298936 : Fermi-LAT search for a high-energy gamma-ray counterpart
  22. LIGO/Virgo G298048: Continued VLA monitoring at 6 GHz
  23. LIGO/Virgo G298936: Identification of a GW Binary Black Hole Candidate
  24. LIGO/Virgo G298048: Global properties and star-formation rate of NGC 4993
  25. LIGO/Virgo G298048: observations of optical counterpart candidate with CHILESCOPE observatory
  26. LIGO/Virgo G298048: ASKAP observations of SSS17a and NGC 4993 at 1.345 GHz
  27. LIGO/Virgo G298048: Gemini-South Near-Infrared Spectroscopy
  28. LIGO/Virgo G298048: VLA observation at 15 GHz
  29. LIGO/Virgo G298048: observations of optical counterpart candidate with CHILESCOPE observatory
  30. LIGO/Virgo G298048: Zadko observations of the OT candidate SSS17a/DLT17ck
  31. LIGO/Virgo G298048: NuSTAR limits on X-ray emission
  32. LIGO/Virgo G298048: ASKAP follow up
  33. LIGO/Virgo G298048: Kanata/HONIR NIR photometry of the possible counterpart of G298048
  34. LIGO/Virgo G298389 : Fermi-LAT search for a high-energy gamma-ray counterpart
  35. LIGO/Virgo G298048: VLA observation at 6 GHz
  36. LIGO/Virgo G298048: Continued VLA observations
  37. LIGO/Virgo G298048: Possible X-ray detection with Swift
  38. LIGO/Virgo G298048: VLBA observations of the possible counterpart SSS17a in NGC 4993
  39. LIGO/Virgo G298048: Possible features in the spectrum of GW counterpart SSS17a
  40. LIGO/Virgo G298048: Rapid Evolution of Possible Counterpart
  41. LIGO/Virgo G298048: Observed fading of optical counterpart SSS17a
  42. LIGO/Virgo G298048: Continued observation for DLT17ck
  43. LIGO/Virgo G298048: Brightening of Possible Counterpart
  44. LIGO/Virgo G298048: Subaru HSC z-band photometry of the possible optical counterpart
  45. LIGO/Virgo G298048: Likelihood of SSS17a Being an Unrelated Extragalactic Transient in NGC 4993
  46. LIGO/Virgo G298048: REM optical/NIR observations
  47. LIGO/Virgo G298048: Pan-STARRS detections and izy photometry of the possible optical/NIR counterpart in NGC4993
  48. LIGO/Virgo G298048: Galaxy-Targeted Optical Followup With Las Cumbres Observatory
  49. LIGO/VIRGO G298048: The Potential Optical Counterpart in NGC 4993 Has Afterglow-Like Colors
  50. LIGO/Virgo G298048: Las Cumbres Observatory Detection of The Possible Optical Counterpart in NGC 4993
  51. LIGO/Virgo G298048: Inspection of archival HST data at the position of the potential optical counterpart
  52. LIGO/Virgo G298048 : Fermi-LAT search for a high-energy gamma-ray counterpart
  53. LIGO/Virgo G298048: correction to the luminosity distance reported in GCN 21509
  54. LIGO/Virgo G298048: Identification of a binary neutron star candidate coincident with Fermi GBM trigger 524666471/170817529
  55. LIGO/Virgo G298048: Fermi GBM trigger 524666471/170817529: LIGO/Virgo Identification of a possible gravitational-wave counterpart
  56. LIGO/Virgo G297595: REM optical/NIR observations
  57. LIGO/Virgo G297595: Pan-STARRS coverage and transients over the first 5hrs
  58. LIGO/Virgo G297595 : Fermi-LAT search for high-energy gamma-ray counterpart
  59. LIGO/Virgo G296853: MASTER SN detection near center error-area
  60. LIGO/Virgo G296853: no INTEGRAL data at the time of the event
  61. LIGO/Virgo G296853: Fermi-LAT search for high-energy gamma-ray counterpart
  62. GRB170730A detecetd by INTEGRAL. Refined analysis
  63. IBAS weak Alert nr.7881: possible GRB 170730A
  64. GRB 170714A: z-band afterglow candidate for OSIRIS/GTC
  65. Fermi GBM Detection of possible burst from AXP 4U 0142+61
  66. GRB 170710B: Swift-XRT and UVOT observations
  67. GRB 170710A: Gemini-S candidate counterpart
  68. GRB 170626A: SAO RAS possible OT detection
  69. LIGO/Virgo G288732: Pan-STARRS coverage of the Fermi/LAT candidate position
  70. LIGO/Virgo G288732: VLA imaging of the possible Fermi/LAT counterpart
  71. LIGO/Virgo G288732: Kiso/KWFC optical imaging of the possible Fermi/LAT counterpart
  72. LIGO/Virgo G288732: HAWC follow-up
  73. LIGO/Virgo G288732: Swift/UVOT follow up of the possible LAT counterpart
  74. LIGO/Virgo G288732: Swift-XRT follow up of the putative LAT counterpart
  75. LIGO/Virgo G288732: INTEGRAL search for a prompt gamma-ray counterpart
  76. LIGO/Virgo G288732: Fermi-LAT detection of a weak candidate
  77. GRB 170607A: Correction on the possible host galaxy identification
  78. Swift Trigger 755873: D50 optical limits
  79. Swift Trigger 755873: a possible GRB
  80. GRB 170531B: Swift/UVOT Detection
  81. GRB 170531B: MASTER Net optical counterpart refind position and magnitude
  82. LIGO/Virgo G268556: optical observations and classification of Pan-STARRS1 transients
  83. LIGO/Virgo G268556: BSA radio observations at 110 MHz
  84. GRB 170524A: Swift detection of a burst (or possible new SGR)
  85. LIGO/Virgo G277583: UH88/SNIFS classification of ATLAS and PS1 transients
  86. GRB 170510A: Global MASTER Net possible OT observations
  87. GRB 170510A: LCO possible counterpart
  88. LIGO/Virgo G284239: Fermi-LAT search for a high-energy gamma-ray counterpart
  89. LIGO/Virgo G284239: INTEGRAL search for a prompt gamma-ray counterpart
  90. Swift Trigger 748858: 15 GHz upper limits from AMI
  91. GRB 170428A: TNG optical observations
  92. Swift Trigger 748858: MASTER-OAFA early optical observations
  93. Swift Trigger 748858: a possible GRB
  94. Konus-Wind observation of GRB 170409A
  95. GRB 170325A: optical observations, possible OT/host detection
  96. Fermi trigger 512347439/GRB 170327A: MASTER-SAAO possible OT detection
  97. LIGO/Virgo G275697: AMI Large Array Search for a Radio Afterglow
  98. IceCube-170321A - IceCube observation of a high-energy neutrino candidate event
  99. IceCube-170312A: MASTER follow-up observations
  100. LIGO/Virgo G277583: ATLAS17cck - a fast declining transient

Advanced

Download all Circulars as a .tar.gz archive (updated once a day):
Looking for U.S. government information and services? Visit USA.gov