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"

7445 results found.

  1. LIGO/Virgo/KAGRA S230627c: Identification of a GW compact binary merger candidate
  2. LIGO/Virgo/KAGRA S230624av: Updated Sky localization
  3. LIGO/Virgo/KAGRA S230624av: Identification of a GW compact binary merger candidate
  4. GRB 230623A: Tiled Swift observations
  5. GRB 230623A: Tiled Swift observations
  6. LIGO/Virgo/KAGRA S230615az: LBT spectroscopic classification of GOTO23hn
  7. LIGO/Virgo/KAGRA S230622ba: Retraction of GW compact binary merger candidate
  8. LIGO/Virgo/KAGRA S230615az: LBT spectroscopic redshift of the host galaxy of GOTO23hn
  9. Fermi GBM-230619: AstroSat CZTI non-detection and upper limits for the sub-threshold candidate
  10. GRB 230622A: Swift detection of a burst
  11. Fermi GBM-230619: A soft subthreshold candidate potentially associated with a subthreshold LIGO/Virgo compact binary merger candidate
  12. LIGO/Virgo/KAGRA S230619bg: one counterpart neutrino candidate from IceCube neutrino searches
  13. LIGO/Virgo/KAGRA S230615az: Wendelstein observations of DESI galaxies and GIT candidates
  14. ZTF23aaoohpy/AT2023lcr: GROWTH-India Telescope follow-up observations
  15. ZTF23aaoohpy/AT2023lcr: GOTO early optical observations and constraint
  16. ZTF23aaoohpy/AT2023lcr: Zwicky Transient Facility discovery of a fast fading red transient
  17. GRB 230618A: Swift detection of a burst
  18. GRB 230616A: Swift ToO observations
  19. LIGO/Virgo/KAGRA S230615az: T80S Search and Candidate Counterpart Identification
  20. LIGO/Virgo/KAGRA S230615az: Xinglong-2.16m photometric observations of GIT candidates
  21. LIGO/Virgo/KAGRA S230529ay: Upper limits from a two-week IceCube neutrino search
  22. LIGO/Virgo/KAGRA S230615az: GOTO candidate counterparts
  23. LIGO/Virgo/KAGRA S230608as: Updated Sky localization
  24. LIGO/Virgo/KAGRA S230606d: Updated Sky localization
  25. LIGO/Virgo/KAGRA S230609u: Updated Sky localization
  26. LIGO/Virgo/KAGRA S230609u: Identification of a GW compact binary merger candidate
  27. ZTF23aamxeqf/AT2023jxk: 1.3m DFOT Optical upper limit
  28. LIGO/Virgo/KAGRA S230608as: Identification of a GW compact binary merger candidate
  29. ZTF and GIT Observations of the Candidate Optical Afterglow AT2023jxk
  30. LIGO/Virgo/KAGRA S230606d: Identification of a GW compact binary merger candidate
  31. Fermi-LAT gamma-ray observations of IceCube-230603A
  32. LIGO/Virgo/KAGRA S230605o: Updated Sky localization
  33. LIGO/Virgo/KAGRA S230601bf: Updated Sky localization
  34. LIGO/Virgo/KAGRA S230605o: Identification of a GW compact binary merger candidate
  35. IceCube-230603A - IceCube observation of a high-energy neutrino candidate track-like event
  36. LIGO/Virgo/KAGRA S230518h: Upper limits from a two-week IceCube neutrino search
  37. LIGO/Virgo/KAGRA S230601bf: Identification of a GW compact binary merger candidate
  38. LIGO/Virgo/KAGRA S230529ay: Upper limits from CALET observations.
  39. LIGO/Virgo/KAGRA S230529ay: AstroSat CZTI non-detection and upper limits
  40. LIGO/Virgo/KAGRA S230529ay: Coverage and upper limits from MAXI/GSC observations
  41. LIGO/Virgo/KAGRA S230529ay: Upper limits from Fermi-GBM Observations
  42. LIGO/Virgo/KAGRA S230529ay: Updated Sky localization and EM Bright Classification
  43. LIGO/Virgo/KAGRA S230529ay: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  44. LIGO/Virgo/KAGRA S230529ay: Identification of a GW compact binary merger candidate
  45. LIGO/Virgo/KAGRA S230518h: Updated Sky localization
  46. LIGO/Virgo/KAGRA S230520ae: Updated Sky localization
  47. LIGO/Virgo/KAGRA S230518h: Upper limits from Glowbug gamma-ray observations
  48. LIGO/Virgo/KAGRA S230518h: TESS observations of the localization region
  49. LIGO/Virgo/KAGRA S230524x: Retraction of GW compact binary merger candidate
  50. IceCube-230524A - IceCube observation of a high-energy neutrino candidate track-like event
  51. LIGO/Virgo/KAGRA S230522n: Upper limits from IceCube neutrino search
  52. LIGO/Virgo/KAGRA S230522a: 2 counterpart neutrino candidates from IceCube neutrino searches
  53. LIGO/Virgo/KAGRA S230521k: Zwicky Transient Facility observations
  54. IPN triangulation of GRB 230518A (short)
  55. LIGO/Virgo/KAGRA S230520ae: Identification of a GW compact binary merger candidate: End-to-End Test
  56. LIGO/Virgo/KAGRA S230520ae: Upper limits from IceCube neutrino search
  57. LIGO/Virgo/KAGRA S230518h: ATCA follow-up of candidate counterparts
  58. LIGO/Virgo/KAGRA S230518h: ATLAS observations of the skymap
  59. LIGO/Virgo/KAGRA S230518h: Swope Search and Candidate Counterpart Identification
  60. LIGO/Virgo/KAGRA S230518h: Coverage and upper limits from MAXI/GSC observations
  61. LIGO/Virgo/Kagra S230518h: NED Galaxies in the Localization Volume
  62. LIGO/Virgo/KAGRA S230518h: AstroSat CZTI non-detection and upper limits
  63. LIGO/Virgo/KAGRA S230518h: Upper limits from Fermi-GBM Observations
  64. LIGO/Virgo/KAGRA S230518h: Updated Sky localization and EM Bright Classification
  65. LIGO/Virgo S230518h: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  66. LIGO/Virgo S230518h: Upper limits from IceCube neutrino search
  67. LIGO/Virgo/KAGRA S230518h: Identification of a GW compact binary merger candidate
  68. GRB 230513A: Zwicky Transient Facility continuous observations of a Fermi Short GRB (Trigger 705709044)
  69. IPN triangulation of GRB 230512A
  70. GRB 230513A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 705709044)
  71. GRB 230512A: Nanshan/NEXT non-detection of GRB afterglow candidate
  72. GRB 230512A: Zwicky Transient Facility non-detection of GRB afterglow candidate
  73. GRB 230512A: Liverpool Telescope observations
  74. GRB 230512A: GIT non detection of afterglow candidate
  75. GRB 230512A: Kitab possible afterglow candidate
  76. GRB 230512A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 705565670)
  77. GRB 230430A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 704533643)
  78. GRB 230511D: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 705537623)
  79. GRB 230512A: Tiled Swift observations
  80. GRB 230510A: LCOGT Optical Upper Limit
  81. IceCube-230511A: IceCube observation of a high-energy neutrino candidate
  82. GRB 230510A: Swift detection of a burst
  83. GRB 230506C: Candidate afterglow observation by D50
  84. GRB 230506C: TSHAO possible afterglow candidate
  85. GRB 230506B: Swift/UVOT Detection
  86. IceCube-230506A: IceCube observation of a high-energy neutrino candidate
  87. GRB 230430A: A short GRB from a neutron star merger
  88. GRB 230427A: Swift detection of a burst with an optical counterpart
  89. Swift Trigger 1165354 is probably not a GRB
  90. GRB 230420A: Swift detection of a burst
  91. IceCube-230416A: IceCube observation of a high-energy neutrino candidate
  92. GRB 230414B (correction GRB name in the GCN 33615): Mondy optical afterglow candidate
  93. GRB 230414A: Mondy optical afterglow candidate
  94. GRB 230414B: Swift detection of a burst
  95. GRB 230409B: Swift detection of a burst
  96. GRB 230307A: JWST NIRSpec observations, possible higher redshift
  97. GRB 230307A: further analysis of the Konus-Wind detection and rest-frame energetics
  98. GRB 230307A: good match with kilonova models
  99. GRB 230307A: short mininum variability timescale compatible with a merger origin
  100. GRB 230405B: 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