Skip to main content
End of Swift Science Operations, CHIME Notices Unavailable During Upgrade. See news and announcements

GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"

45782 results found.

  1. EP240506a: TRT optical upper limit
  2. EP240506a: BOOTES Network optical upper limit
  3. LIGO/Virgo/KAGRA S240507p: Updated Sky localization and EM Bright Classification
  4. LIGO/Virgo/KAGRA S240422ed: Upper limits from a two-week IceCube neutrino search
  5. Fermi trigger No 736733320: Global MASTER-Net observations report
  6. EP240506a: Optical upper limit with Kinder observations
  7. IPN triangulation of GRB 240504A
  8. GRB 240502A: 1.3m DFOT Optical upper limit
  9. EP240506a: EP-WXT detection of a new fast X-ray transient
  10. LIGO/Virgo/KAGRA S240507p: Identification of a GW compact binary merger candidate
  11. LIGO/Virgo/KAGRA S240422ed: Additional WINTER near-infrared J-band observations
  12. LIGO/Virgo/KAGRA S240422ed: Swope Follow-up of AT2024hfr and AT2024hfs
  13. GRB 240504A: Swift/BAT-GUANO detection of a burst outside the coded FOV
  14. Fermi GBM triggers 736668287/240506253 and 736669277/240506265 are not GRBs
  15. LIGO/Virgo/KAGRA S240505av: Updated Sky localization and EM Bright Classification
  16. Fermi trigger No 736564880: Global MASTER-Net observations report
  17. LIGO/Virgo/KAGRA S240505av: Identification of a GW compact binary merger candidate
  18. IceCube-240424A: GRANDMA Optical Upper Limit of Fermi J2151.3+0220
  19. GRB 240502C: Zeiss-1000 at Koshka observatory observations of GOTO optical counterpart candidates
  20. Fermi trigger No 736461232: Global MASTER-Net observations report
  21. IPN triangulation of GRB 240501B and GRB 240501A - possible episodes of ultra long GRB
  22. Fermi GRB 240504A: Global MASTER-Net observations report
  23. Fermi trigger No 736472503: Global MASTER-Net observations report
  24. GW170817: VLA observations at ~5.5 yrs since merger
  25. GRB 240503A: AstroSat CZTI detection
  26. GRB 240504A: BALROG localization (Fermi Trigger 736492377 / GRB 240504217)
  27. GRB 240504A: Fermi GBM Final Real-time Localization
  28. Fermi trigger No 736387941: Global MASTER-Net observations report
  29. LXT 240402A / GRB 240402B: VLT X-shooter redshift of host
  30. GRB 240502A: GOTO optical upper limit
  31. Fermi trigger No 736379109: Global MASTER-Net observations report
  32. GRB 240502A: Fermi GBM Observation
  33. GRB 240415A 1.3m DFOT Optical upper limit
  34. GRB 240502C: GOTO possible optical counterpart candidates
  35. LIGO/Virgo/KAGRA S240501an: Updated Sky localization and EM Bright Classification
  36. LIGO/Virgo/KAGRA S240430ca: Updated Sky localization and EM Bright Classification
  37. Fermi GRB 240502B: Global MASTER-Net observations report
  38. GRB 240502C: Fermi GBM Final Localization
  39. Fermi GRB 240502A: Global MASTER-Net observations report
  40. GRB 240501B: GRBAlpha detection
  41. GRB 240430A: GRBAlpha detection
  42. GRB 240502B: Fermi GBM Final Real-time Localization
  43. LIGO/Virgo/KAGRA S240422ed: GECKO/KMTNet Transient Candidates
  44. Integral GRB240502.23: Global MASTER-Net observations report
  45. GRB 240502A long GRB detected by INTEGRAL
  46. GRB 240502A: Fermi GBM Final Real-time Localization
  47. LIGO/Virgo/KAGRA S240422ed: Host redshifts of AT2024hfq, AT2024hfu, and AT2024hmo from DBSP
  48. Fermi GRB 240501A: Global MASTER-Net observations report
  49. Fermi trigger No 736197684: Global MASTER-Net observations report
  50. GRB 240426A: VZLUSAT-2 detection
  51. GRB 240425A: VZLUSAT-2 detection
  52. MeerKAT Discovery of a Probable Radio Counterpart to EP240414a
  53. GRB240430A: Fermi GBM Final Localization
  54. GRB 240501B: AstroSat CZTI detection
  55. GRB 240501A: Fermi GBM Final Real-time Localization
  56. GRB 240408B: VZLUSAT-2 detection
  57. GRB 240407A: VZLUSAT-2 detection
  58. LIGO/Virgo/KAGRA S240501an: Identification of a GW compact binary merger candidate
  59. X-ray transient EP240414a: Detection of associated supernova
  60. LIGO/Virgo/KAGRA S240430ca: Updated Sky localization and EM Bright Classification
  61. LIGO/Virgo/KAGRA S240430ca: Identification of a GW compact binary merger candidate
  62. LIGO/Virgo/KAGRA S240422ed: GECKO/7DT ToO observations
  63. Additional DECam GW-MMADS Candidates from three nights of observations
  64. GRB 240425A: GRBAlpha detection
  65. Fermi-LAT gamma-ray observations of IceCube-240424A
  66. LIGO/Virgo/KAGRA S240426s: Updated Sky localization
  67. LIGO/Virgo/KAGRA S240422ed: SRG/eROSITA archival upper limit for EP240426a
  68. LIGO/Virgo/KAGRA S240426dl: Updated Sky localization
  69. GRB 240429A: Fermi GBM Final Real-time Localization
  70. LIGO/Virgo/KAGRA S240428dr: Updated Sky localization
  71. LIGO/Virgo/KAGRA S240422ed: GECKO/KMTNet ToO observations
  72. LIGO/Virgo/KAGRA S240429an: Retraction of GW compact binary merger candidate
  73. LIGO/Virgo/KAGRA S240422ed: ENGRAVE VLT/XShooter spectroscopy of the host galaxy of J-GEM24a
  74. LIGO/Virgo/KAGRA S240428dr: Identification of a GW compact binary merger candidate
  75. Fermi GRB 240428A: Global MASTER-Net observations report
  76. GRB 240428A: Fermi GBM Final Real-time Localization
  77. LIGO/Virgo/KAGRA S240422ed: J-band non-detection of J-GEM24a
  78. LIGO/Virgo/KAGRA S240422ed: DDOTI Optical Upper Limit for J-GEM24a
  79. EP240426b: AST3-2 optical upper limit
  80. LIGO/Virgo/KAGRA S240422ed: Observations with 1.6m Mephisto
  81. LIGO/Virgo/KAGRA S240422ed: A transient discovered from Subaru/MOIRCS near-infrared observations by J-GEM Collaboration
  82. LIGO/Virgo S240422ed: Swift XRT observation of EP240426a
  83. LIGO/Virgo/KAGRA S240422ed: NOT optical observations of EP240426a
  84. EP240426b: EP-WXT detection of a new fast X-ray transient
  85. LIGO/Virgo/KAGRA S240422ed: Archival radio detection of EP240426a
  86. LIGO/Virgo/KAGRA S240422ed: Swope Follow-up of AT2024hfq, AT2024hfr, AT2024hfs, and AT2024hfx
  87. LIGO/Virgo/KAGRA S240422ed: BOOTES-6/DPRT optical upper limits for EP240426a
  88. LIGO/Virgo/KAGRA S240422ed: GRANDMA Optical Upper Limits for EP240426a
  89. LIGO/VIRGO/KAGRA S240422ed: Historical variability for EP240426a
  90. GRB 240426A: AstroSat CZTI detection
  91. EP240426a: YAHPT optical upper limit
  92. XMM-Newton observation of EP240426a
  93. LIGO/Virgo/KAGRA S240426dl: Identification of a GW compact binary merger candidate
  94. LIGO/Virgo/KAGRA S240422ed: BOOTES-4/MET Optical Upper Limits for EP240426a
  95. LIGO/Virgo/KAGRA S240422ed: EP-FXT Detection of the Potential Opitcal Electromagnetic Counterpart AT 2024hfq Reported by DECam
  96. GRB 240414A: NOEMA detection
  97. LIGO/Virgo/KAGRA S240422ed: EP240426a possible optical detection
  98. LIGO/Virgo/KAGRA S240422ed: Continued Magellan Observations
  99. EP240426a: GMG optical upper limit
  100. LVK S240422ed: Further Swift-XRT followup of three sources

Advanced

Download all Circulars as a .tar.gz archive (updated once a day):
Questions or comments?
Contact GCN directly.
Have you found a bug in GCN?
Open an issue.
Want to contribute code to GCN?
Get involved on GitHub.

gcn.nasa.gov

A service of the Astrophysics Science Division at NASA Goddard Space Flight Center

Looking for U.S. government information and services? Visit USA.gov