Skip to main content
Circulars over Kafka event name backfill. 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"

24640 results found.

  1. LIGO/Virgo/KAGRA S241127aj: NED Galaxies in the Localization Volume
  2. EP241126a: Optical Upper limits with Kinder observations
  3. IPN triangulation of GRB 241114B
  4. EP trigger ID 01709122294: 1.6m Mephisto multi-band optical observations
  5. EP241126a: GSP detects optical counterpart
  6. EP241126a: TRT optical counterpart detection
  7. LIGO/Virgo/KAGRA S241127aj: Identification of a GW compact binary merger candidate
  8. EP241126a: EP detection of a fast X-ray transient
  9. LIGO/Virgo/KAGRA S241125n: COLIBRÍ Upper Limits on Optical Counterparts to Two of the Swift/XRT Sources
  10. LIGO/Virgo/KAGRA S241125n: SAGUARO follow-up observations with the MMT
  11. LIGO/Virgo/KAGRA S241125n: DDOTI Optical Upper Limits
  12. LIGO/Virgo/KAGRA S241125n: Gaoyazi/GOT optical observations
  13. GECAM detection of a short burst from SGR 1830
  14. LIGO/VIRGO/KAGRA S241125n: GROWTH-India telescope optical observations
  15. LIGO/Virgo S241125n: Swift XRT observations, 5 X-ray sources
  16. LIGO/Virgo/KAGRA S241125n: HCT upper limit
  17. LIGO/Virgo/KAGRA S241125n: Upper limits from Konus-Wind observations
  18. GRB 241026A: radio detection with the VLA
  19. EP241125a: Optical upper limit with Kinder observations
  20. EP241125a: EP detection of an X-ray transient
  21. LIGO/Virgo/KAGRA S241125n: COLIBRÍ Upper Limits on a Optical Counterpart at the BAT Position
  22. LIGO/Virgo/KAGRA S241125n: Upper limits from Fermi-GBM Observations
  23. LIGO/Virgo/KAGRA S241125n: Updated Coincidence with External Event
  24. LIGO/Virgo/KAGRA S241125n: Kinder optical upper limit in the BAT error region
  25. LIGO/Virgo/KAGRA S241125n: Updated Sky localization
  26. LIGO/Virgo/KAGRA S241125n: Updated Coincidence with External Event
  27. LIGO/Virgo/KAGRA S241125n: No counterpart candidates in INTEGRAL SPI-ACS prompt observation, comparisong with Swift/BAT counterpart
  28. LIGO/Virgo/KAGRA S241109bn: Upper limits from a two-week IceCube neutrino search
  29. LIGO/Virgo/KAGRA S241125n: Updated Sky localization and Coincidence with External Event
  30. LIGO/Virgo/KAGRA S241125n: Swift/BAT-GUANO candidate counterpart
  31. LIGO/Virgo/KAGRA S241125n: Identification of a GW compact binary merger candidate
  32. LIGO/Virgo/KAGRA S241122a: Updated Sky localization and Source Classification
  33. LIGO/Virgo/KAGRA S241122a: Identification of a GW compact binary merger candidate
  34. IPN triangulation of GRB 241117A
  35. GRB 241026A: VIRT Optical Upper Limit
  36. GRB 241025A: VIRT Optical Upper Limit
  37. GRB241120A: OHP/T193 optical observations
  38. EP241021a and EP241026b: Keck/LRIS spectroscopic observations
  39. GRB 241120A: Mondy and AbAO optical observations
  40. EP241119a: Optical upper limits with Kinder observations
  41. EP trigger ID 01709122294: the X-ray transient is likely a stellar flare event
  42. EP241119a: GIT optical upper limits
  43. EP241119a : J-band observations with WINTER
  44. GRB 241120A: Fermi GBM Observation
  45. EP241119a: EP detection of a fast X-ray transient
  46. GRB241120A: a long GRB detected by INTEGRAL
  47. GRB 241112B: Mephisto further optical observations
  48. GRB 241030A: J-band observations
  49. GRB 241115a: PRIME near-infrared upper limits
  50. GRB 241117A: Swift/BAT-GUANO localization skymap of a burst
  51. LIGO/Virgo/KAGRA S241116cq: Upper limits from Swift/BAT-GUANO
  52. GRB 241115B: Fermi GBM Observation
  53. LIGO/Virgo/KAGRA S241114y: Updated Sky localization
  54. Updates to IceCube realtime alert system for muon tracks
  55. GRB 241117A: SVOM/GRM observation of a short burst with extended emission
  56. GRB 241117A: Fermi GBM Detection
  57. IceCube-Cascade 241116A: Upper limits from a search for additional neutrino events in IceCube
  58. LIGO/Virgo/KAGRA S241116cq: Updated Sky localization
  59. GRB 241115B: Swift/BAT-GUANO localization skymap of a long burst
  60. GRB 241115C: Fermi GBM Observation
  61. GRB 241115A: Swift-XRT afterglow detection
  62. LIGO/Virgo/KAGRA S241116cq: Identification of a GW compact binary merger candidate
  63. EP241115a/GRB 241115D: Optical upper limits with Kinder observations
  64. GRB 241115A: Mephisto upper limits
  65. GRB 241113B: Mephisto upper limits
  66. EP241115a/GRB 241115D: Swift/XRT follow-up observation
  67. GRB 241115D / EP 241115a: SVOM/GRM observation
  68. EP241113a: Swift XRT weak detection
  69. GRB 241115A: Fermi GBM Observation
  70. GRB 241115A: LCOGT Optical Upper Limits
  71. GRB 241115C: Swift/BAT-GUANO localization skymap of a burst
  72. LIGO/Virgo/KAGRA S241114bi: Updated Sky localization and EM Bright Classification
  73. LIGO/Virgo/KAGRA S241113p: Updated Sky localization
  74. EP241115a: EP detection of a fast X-ray transient
  75. Swift GRB 241115A: Global MASTER-Net observations report
  76. Fermi GRB 241115A: Global MASTER-Net observations report
  77. GRB 241115A: Swift detection of a burst
  78. EP 241113a: LBT possible optical counterpart
  79. LIGO/Virgo/KAGRA S241114bi: Upper limits from Fermi-GBM Observations
  80. LIGO/Virgo/KAGRA S241114bi: Coverage and upper limits from MAXI/GSC observations
  81. GRB 241113A: Swift-BAT refined analysis
  82. LIGO/Virgo/KAGRA S241114bi: Identification of a GW compact binary merger candidate
  83. GRB 241113A: PRIME near-infrared upper limits
  84. EP241113a: Global MASTER-Net observations report
  85. GRB 241113B: J-band upper limit from WINTER
  86. GRB 241113A: J-band observations with WINTER
  87. EP241113a : J-band observations with WINTER
  88. GRB 241030A: LCO optical observation
  89. GRB 241113B: Swift-XRT observations
  90. IceCube-241113A: Upper limits from a search for additional neutrino events in IceCube
  91. GRB 241113A: 1.6m Mephisto and 50cm array optical upper limits
  92. EP241113b/GRB 241113B: EP detection of GRB 241113B
  93. Fermi-LAT gamma-ray observations of IceCube-241113A
  94. LIGO/Virgo/KAGRA S241114y: Identification of a GW compact binary merger candidate
  95. GRB 241113A: Swift-XRT refined Analysis
  96. GRB 241113A: Swift/UVOT Detection
  97. GRB 241113A: REM detection of the optical/NIR afterglow
  98. LIGO/Virgo/KAGRA S241113p: Identification of a GW compact binary merger candidate
  99. GRB 241113A: LCO optical observations
  100. GRB 241112B: GMG Optical Upper Limit

Advanced

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