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. Konus-Wind detection of GRB 241117A
  2. IPN triangulation of GRB 241117A
  3. EP241021a and EP241026b: Keck/LRIS spectroscopic observations
  4. EP trigger ID 01709065118: Keck/LRIS spectroscopic observations
  5. GRB 241120A: Mondy and AbAO optical observations
  6. GRB 241113A: Possible ATCA Radio detection
  7. EP241115a/GRB 241115D: Swift/XRT follow-up observation
  8. EP 241113a: LBT possible optical counterpart
  9. IceCube-241113A - IceCube observation of a high-energy neutrino candidate track-like event
  10. LIGO/Virgo/KAGRA S241109bn: ATLAS observations and discovery of the potential counterpart AT2024aawt
  11. GRB 241030A: Mondy optical observations
  12. LIGO/Virgo/KAGRA S241102br: OHP/T193 optical observations
  13. EP241101a: Possible detection of an optical counterpart with FTW
  14. GRB 241030A / EP241030a: GMG possible spectroscopic redshift at z ~ 1.4
  15. GRB 241030A: detection of the bright optical counterpart in ATLAS forced photometry
  16. GRB 241030A: Keck/LRIS spectroscopic redshift z = 1.411
  17. EP 241026b: LBT possible optical counterpart (brightening source)
  18. GRB 240821A: Keck/LRIS spectroscopic observations
  19. GRB 241026A: SAO RAS observations of possible optical afterglow
  20. IceCube-241006A - IceCube observation of a high-energy neutrino candidate track-like event
  21. EP trigger ID 01709064214: GOTO confirms detection as a flare star
  22. IceCube-240929A - IceCube observation of a high-energy neutrino candidate track-like event
  23. EP240918a: Swift-XRT observation
  24. EP240918a: YAHPT Optical Upper Limit
  25. GRB 240912A: Swift-BAT refined analysis
  26. Fast X-ray Transient EP240801a: GMRT radio observations
  27. GRB 240905E: CrAO Optical Afterglow observations, possible OT candidate
  28. GRB 240819A as a likely X-Ray Flash
  29. GRB 240828B : Detection of a possible very soft X-ray transient by SVOM/ECLAIRs
  30. EP240801a: Keck/LRIS spectroscopic redshift confirmation
  31. IceCube-240808A - IceCube observation of a high-energy neutrino candidate track-like event
  32. The EP-WXT trigger 01709018832 on August 7th is likely a flaring star
  33. EP240801a: NOT optical observations
  34. IceCube-240725A - IceCube observation of a high-energy neutrino candidate track-like event
  35. IceCube-240721A - IceCube observation of a high-energy neutrino candidate track-like event
  36. EP240708a: X-ray follow-up observations with Swift/XRT
  37. The EP-WXT source triggered on July 14th is likely a flaring star
  38. GRB 240713A: J-band upper limit from WINTER
  39. GRB240713A: X-ray follow-up observation with EP-FXT
  40. EP240708a: X-ray follow-up observations with EP/FXT and Swift/XRT
  41. EP240703a and EP240703b: Swift/XRT upper limits
  42. EP240702a: Swift/XRT upper limit
  43. EP240626a: Montarrenti Observatory optical upper limit
  44. EP240618a: NOT further optical observations
  45. X-ray transient EP240618a: Fermi/GBM non-detection
  46. EP240618a: Swift/XRT upper limit
  47. EP240617a: tentative Swift/XRT detection of the afterglow
  48. GRB 240615A: possible transient detection from Wendelstein observations
  49. EP240618a: OHP/T193 MISTRAL i' and Y band upper limits
  50. Swift Trigger 1235109: a possible GRB 240606A
  51. GRB 240603B: Swift detection of a possible burst
  52. GRB 240529A: MASTER prompt OT detection
  53. The EP-WXT source triggered on June 1st is likely a flaring star
  54. EP240518a: GSP optical upper limit
  55. EP240518a: possibly identified with a flare star by EP-FXT
  56. GRB 240514E: A possible candidate BD-21 1074
  57. GRB 240502C: Zeiss-1000 at Koshka observations of GOTO24bao optical counterpart candidate
  58. GRB 240514B: GOTO candidate optical counterpart
  59. LIGO/Virgo/KAGRA S240422ed: P200 observations of AT2024hit
  60. LIGO/Virgo/KAGRA S240422ed: Swope Follow-up of AT2024hfr and AT2024hfs
  61. GRB 240502C: Zeiss-1000 at Koshka observatory observations of GOTO optical counterpart candidates
  62. IPN triangulation of GRB 240501B and GRB 240501A - possible episodes of ultra long GRB
  63. GRB 240502C: GOTO possible optical counterpart candidates
  64. LIGO/Virgo/KAGRA S240422ed: Host redshifts of AT2024hfq, AT2024hfu, and AT2024hmo from DBSP
  65. LIGO/Virgo/KAGRA S240422ed: DDOTI Optical Upper Limit for J-GEM24a
  66. LIGO/Virgo/KAGRA S240422ed: Swope Follow-up of AT2024hfq, AT2024hfr, AT2024hfs, and AT2024hfx
  67. LIGO/Virgo/KAGRA S240422ed: BOOTES-6/DPRT optical upper limits for EP240426a
  68. LIGO/Virgo/KAGRA S240422ed: GRANDMA Optical Upper Limits for EP240426a
  69. LIGO/VIRGO/KAGRA S240422ed: Historical variability for EP240426a
  70. EP240426a: YAHPT optical upper limit
  71. LIGO/Virgo/KAGRA S240422ed: BOOTES-4/MET Optical Upper Limits for EP240426a
  72. LIGO/Virgo/KAGRA S240422ed: EP240426a possible optical detection
  73. LIGO/Virgo/KAGRA S240422ed: Continued Magellan Observations
  74. LIGO/Virgo/KAGRA S240422ed: EP-FXT detection of a candidate counterpart EP240426a
  75. LIGO/Virgo/KAGRA S240422ed: Magellan Follow-up Observations of Swift/XRT candidates
  76. S240422ed: BlackGEM/MeerLICHT transient detection AT2024hgl/MLTJ080628.10-250116.4
  77. S240422ed: MeerLICHT/BlackGEM photometry on AT2024hfx and archival ZTF detection
  78. LIGO/Virgo/KAGRA S240422ed: Magellan Spectrum of GW-MMADS Candidate AT2024hdo Indicates a Type II SN
  79. LIGO/Virgo/KAGRA S240422ed: Archival BlackGEM/MeerLICHT detections of AT 2024hdr & AT 2024hdq
  80. LIGO/Virgo/KAGRA S240422ed: Vetting of DECam Candidates Using Real-Time Resources and SAGUARO Infrastructure
  81. IceCube-240424A - IceCube observation of a high-energy neutrino candidate track-like event
  82. LIGO/Virgo/KAGRA S240422ed: MOSFIRE spectroscopy of the DECam GW-MMADS candidate AT 2024hdn
  83. LIGO/Virgo S240422ed: Swift-XRT detection of 3 possible counterparts
  84. LIGO/Virgo/KAGRA S240422ed: Continued Imaging of Mag24a
  85. LIGO/Virgo/KAGRA S240422ed: Magellan Detection of a Potential Electromagnetic Counterpart
  86. LIGO/Virgo/KAGRA S240422ed: no candidate counterparts from ATLAS observations
  87. GRB 240419A: Possible ATCA radio detection
  88. LIGO/Virgo/KAGRA S240422ed: Magellan Observations
  89. LIGO/Virgo/KAGRA S240422ed: Identification of a GW compact binary merger candidate
  90. GRB240418A - Candidate afterglow from NIRES
  91. IceCube-240419A - IceCube observation of a high-energy neutrino candidate track-like event
  92. IceCube-240419A - IceCube observation of a high-energy neutrino candidate track-like event
  93. EP240417a: YAHPT Optical Upper Limits
  94. LIGO/Virgo/KAGRA S240413p: STEP - T80S Search and Candidate Counterpart Identification
  95. EP240416a: Kinder optical counterpart candidate
  96. GRB 240415A: Mondy optical transient detection
  97. LXT 240402A/GRB 240402B: Swift follow-up observations
  98. EP240414a: Kinder optical counterpart candidate possibly associated with the galaxy SDSS J124601.99-094309.3
  99. EP240413a: possible detection of the X-ray emission with EP-FXT after 14 hours
  100. GRB 240414A: Swift detection of a burst

Advanced

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