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"

32541 results found.

  1. AT2023lcr: Pan-STARRS & ATLAS Observations
  2. ZTF23aaoohpy/AT2023lcr: Keck/LRIS spectroscopy and redshift
  3. ZTF23aaoohpy/AT2023lcr: Xinglong-2.16m optical observations
  4. LIGO/Virgo/KAGRA S230615az: Wendelstein observations of DESI galaxies and GIT candidates
  5. ZTF23aaoohpy/AT2023lcr: Liverpool Telescope detection
  6. ZTF23aaoohpy/AT2023lcr: OHP/T193 and OHP/T120 optical follow-up observations
  7. ZTF23aaoohpy/AT2023lcr: GROWTH-India Telescope follow-up observations
  8. GRB 230618A: Osservatorio Astronomico Nastro verde upper limit
  9. ZTF23aaoohpy/AT2023lcr: GOTO early optical observations and constraint
  10. LIGO/Virgo/KAGRA S230615az: GRANDMA observations of GOTO and GIT candidates
  11. GRB 230618A: Swift/UVOT Upper Limits
  12. GRB 230618A: KAIT Optical Observations
  13. Swift GRB 230618A: Global MASTER-Net observations report
  14. GRB230618A: LCOGT Optical Observations
  15. GRB 230616A: Swift ToO observations
  16. LIGO/Virgo/KAGRA S230615az: Non-Detections of GROWTH-India Candidates from GECKO Optical Observations
  17. GRB 230614C: GRBAlpha detection
  18. GRB 230616A: AstroSat CZTI detection
  19. LIGO/Virgo/KAGRA S230615az: Xinglong-2.16m photometric observations of GIT candidates
  20. GRB 230614C: AstroSat CZTI detection
  21. GRB 230614B: Fermi GBM Observation
  22. GRB 230614B: Swift/BAT-GUANO detection outside the coded FOV
  23. GRB 230606A: LCOGT Optical Observations
  24. LIGO/Virgo/KAGRA S230608as: Updated Sky localization
  25. LIGO/Virgo/KAGRA S230606d: Updated Sky localization
  26. LIGO/Virgo/KAGRA S230609u: Updated Sky localization
  27. GRB 230608A: CALET Gamma-Ray Burst Monitor detection
  28. GRB 230608A: AstroSat CZTI detection
  29. LIGO/Virgo/KAGRA S230609u: Identification of a GW compact binary merger candidate
  30. ZTF23aamxeqf/AT2023jxk: 1.3m DFOT Optical upper limit
  31. LIGO/Virgo/KAGRA S230608as: Identification of a GW compact binary merger candidate
  32. Fermi GRB 230603A: Global MASTER-Net observations report
  33. GRB 230506B: Chandra localization of the X-ray afterglow
  34. GRB 230606A: Swift-BAT refined analysis
  35. GRB 230606A: Gaoyazi/GOT optical upper limit
  36. GRB 230606A: Fermi GBM Observation
  37. GRB 230604A: GRBAlpha detection
  38. GRB 230606A: Swift/UVOT Upper Limits
  39. LIGO/Virgo/KAGRA S230606d: Identification of a GW compact binary merger candidate
  40. Fermi-LAT gamma-ray observations of IceCube-230603A
  41. LIGO/Virgo/KAGRA S230605o: Updated Sky localization
  42. IceCube-230603A: Upper limits from a search for additional neutrino events in IceCube
  43. LIGO/Virgo/KAGRA S230601bf: Updated Sky localization
  44. LIGO/Virgo/KAGRA S230605o: Identification of a GW compact binary merger candidate
  45. LIGO/Virgo/KAGRA S230601bf: Identification of a GW compact binary merger candidate
  46. GRB 230525A: CALET Gamma-Ray Burst Monitor detection
  47. LIGO/Virgo/KAGRA S230529ay: Upper limits from CALET observations.
  48. LIGO/Virgo/KAGRA S230529ay: Coverage and upper limits from MAXI/GSC observations
  49. LIGO/Virgo/KAGRA S230529ay: Upper limits from Fermi-GBM Observations
  50. LIGO/Virgo/KAGRA S230529ay: Updated Sky localization and EM Bright Classification
  51. LIGO/Virgo/KAGRA S230529ay: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  52. LIGO/Virgo/KAGRA S230529ay: Identification of a GW compact binary merger candidate
  53. LIGO/Virgo/KAGRA S230518h: Updated Sky localization
  54. LIGO/Virgo/KAGRA S230520ae: Updated Sky localization
  55. Fermi-LAT gamma-ray observations of IceCube-230524A
  56. LIGO/Virgo/KAGRA S230518h: Upper limits from Glowbug gamma-ray observations
  57. GRB 230510A: Swift-BAT refined analysis
  58. GRB 230525A: Fermi GBM Detection
  59. LIGO/Virgo/KAGRA S230518h: TESS observations of the localization region
  60. GRB 230523B: GRBAlpha detection
  61. GRB 230524A: Fermi GBM Observation
  62. GRB 230524A: AstroSat CZTI detection
  63. GRB 230524A: AGILE detection
  64. LIGO/Virgo/KAGRA S230521k: MASTER new OT discovery
  65. GRB 230523B: Name correction from GCN Circular 33859
  66. LIGO/Virgo/KAGRA S230521k: Additional candidates from Zwicky Transient Facility
  67. LIGO/Virgo/KAGRA S230518h: Swift/UVOT Upper Limits for MeerLICHT candidates: AT2023ixg and AT2023iyb
  68. GRB 230518B: VZLUSAT-2 detection
  69. Fermi Gamma-ray Burst Monitor trigger 706338208/230521211 is not a GRB
  70. IPN triangulation of GRB 230518A (short)
  71. GRB 230520A: CALET Gamma-Ray Burst Monitor detection
  72. LIGO/Virgo/KAGRA S230520ae: Identification of a GW compact binary merger candidate: End-to-End Test
  73. GRB 230520B is not a GRB
  74. LIGO/Virgo/KAGRA S230518h: ATCA follow-up of candidate counterparts
  75. LIGO/Virgo/KAGRA S230518h: GECKO tiling observations with KMTNet
  76. LIGO/Virgo/KAGRA S230518h: Swift/UVOT Upper Limits for Swope candidates: SSS23a, SSS23b and SSS23c
  77. LIGO/Virgo/KAGRA S230518h: ATLAS observations of the skymap
  78. LIGO/Virgo/KAGRA S230518h: Swope Search and Candidate Counterpart Identification
  79. GRB 230518A: Fermi GBM Observation
  80. LIGO/Virgo/KAGRA S230518h: Upper limits from Konus-Wind observations
  81. GRB 230518A: Swift/BAT-GUANO detection
  82. LIGO/Virgo/KAGRA S230518h: Coverage and upper limits from MAXI/GSC observations
  83. LIGO/Virgo/KAGRA S230518h: AstroSat CZTI non-detection and upper limits
  84. LIGO/Virgo/KAGRA S230518h: Upper limits from Fermi-GBM Observations
  85. LIGO/Virgo/KAGRA S230518h: Updated Sky localization and EM Bright Classification
  86. LIGO/Virgo S230518h: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  87. LIGO/Virgo/KAGRA S230518h: Identification of a GW compact binary merger candidate
  88. GRB 230513A: Zwicky Transient Facility continuous observations of a Fermi Short GRB (Trigger 705709044)
  89. GRB 230510B: GRBAlpha detection
  90. Improved IPN triangulation of GRB 230512A
  91. GRB 230510B: Fermi GBM detection
  92. IPN triangulation of GRB 230511D (short)
  93. IPN triangulation of GRB 230512A
  94. GRB 230513A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 705709044)
  95. GRB 230512A: Nanshan/NEXT non-detection of GRB afterglow candidate
  96. GRB 230512A: Zwicky Transient Facility non-detection of GRB afterglow candidate
  97. GRB 230512A: Liverpool Telescope observations
  98. GRB 230512A: GIT non detection of afterglow candidate
  99. GRB 230512A: Kitab possible afterglow candidate
  100. GRB 230512A: GRBAlpha detection

Advanced

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