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"

6098 results found.

  1. LIGO/Virgo S190923y: optical spectrum of MASTER detected transient
  2. LIGO/Virgo S190930t: Transient found in Swift/UVOT counterpart search
  3. LIGO/Virgo S190930t: No counterpart candidates in Fermi-LAT observations
  4. LIGO/Virgo S190930s: No counterpart candidates in Fermi-LAT observations
  5. LIGO/Virgo S190930t: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  6. LIGO/Virgo S190930s: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  7. GRB 190926A: Swift-XRT refined Analysis
  8. LIGO/Virgo S190924h: No counterpart candidates in Fermi-LAT observations
  9. LIGO/Virgo S190924h: no counterpart candidates in AGILE-GRID observations
  10. Fermi-LAT Gamma-ray Observations of IceCube-190922B
  11. LIGO/Virgo S190924h: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  12. LIGO/Virgo S190923y: No counterpart candidates in Fermi-LAT observations
  13. Fermi-LAT Gamma-ray Observations of IceCube-190922A
  14. IceCube-190922B - HAWC follow-up
  15. LIGO/Virgo S190923y: INTEGRAL IBIS coded-masked imaging observations of part of the localization area and further all-sky upper limits
  16. LIGO/Virgo S190923y: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  17. IceCube-190922A - HAWC follow-up
  18. IceCube-190922A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  19. GRB 190919B: Swift-XRT observations
  20. GRB 190919B: GROND detection of the NIR afterglow
  21. HAWC-190916A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  22. Alert from the HAWC Burst Monitor HAWC-190917A
  23. LIGO/Virgo S190915ak: No counterpart candidates in Fermi-LAT observations
  24. LIGO/Virgo S190915ak: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  25. LIGO/Virgo S190910h: No counterpart candidates in Fermi-LAT observations
  26. LIGO/Virgo S190910d: No counterpart candidates in Fermi-LAT observations
  27. LIGO/Virgo S190910h: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  28. LIGO/Virgo S190910d: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  29. GRB 190823A: Swift-XRT afterglow detection
  30. GRB 190903A: Fermi GBM detection
  31. Chandra observations of GW170817 ~740-743 days since merger
  32. LIGO/Virgo S190901ap: No counterpart candidates in Fermi-LAT observations
  33. LIGO/Virgo S190901ap: No counterpart candidates in INTEGRAL SPI-ACS,prompt observation
  34. GRB 190829A: TNG imaging of the NIR afterglow
  35. GRB 190829A: Fermi GBM detection
  36. GRB 190829A: Fermi-LAT Upper Limits
  37. GRB 190829A: GROND detection of the Optical/NIR Afterglow
  38. GRB 190829A: Swift-XRT refined Analysis
  39. GRB 190828B: Swift-XRT refined Analysis
  40. GRB 190828A: Swift-XRT observations
  41. LIGO/Virgo S190828l: No counterpart candidates in Fermi-LAT observations
  42. GRB 190828B: Fermi GBM observation
  43. LIGO/Virgo S190828j: No counterpart candidates in Fermi-LAT observations
  44. LIGO/Virgo S190814bv: no variation of DESGW candidates AT 2019onj and AT 2019okr from ENGRAVE VLT/HAWK-I observations, and archival detection
  45. LIGO/Virgo S190828l: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  46. LIGO/Virgo S190828j: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  47. LIGO/Virgo S190814bv: SALT optical spectrum of candidate DG19aqbkc
  48. LIGO/Virgo S190814bv: LCO Photometry of DG19wxnjc/AT2019npv
  49. GRB 190823A: Swift-XRT observations
  50. GRB 190816A: Swift-XRT afterglow detection
  51. GRB 190824A: Swift-XRT refined Analysis
  52. GRB 190824A: Fermi GBM observation
  53. LIGO/Virgo S190814bv: GROND follow-up observations of AT2019npv
  54. LIGO/Virgo S190814bv: ENGRAVE VLT/HAWK-I observations and archival detection of the CFHT candidate
  55. GRB 190821A: Swift-XRT refined Analysis
  56. GRB 190821A: Fermi GBM observation
  57. Fermi GBM-190816: No counterpart candidates in Fermi-LAT observations
  58. Fermi-LAT Gamma-ray Observations of IceCube-190819A
  59. IceCube-190819A - HAWC follow-up
  60. Fermi GBM-190816: Location-dependent upper limits from INTEGRAL/SPI-ACS prompt observation
  61. IceCube-190819A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  62. LIGO/Virgo S190814bv: No strong counterpart candidates in Swift/XRT observations
  63. GRB 190816A: Swift-XRT observations
  64. LIGO/Virgo S190814bv: Fermi-LAT search for a high-energy gamma-ray counterpart
  65. LIGO/Virgo S190814bv: GRAWITA TNG infrared imaging of desgw-190814e, DG19sevhc and selected galaxies
  66. LIGO/Virgo S190814bv: Konus-Wind observations
  67. LIGO/Virgo S190814bv: GRAWITA TNG infrared imaging of selected galaxies
  68. LIGO/Virgo S190814bv: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  69. HAWC-190806A: upper limits from INTEGRAL SPI-ACS and IBIS prompt observation
  70. HAWC-190806A: Swift-XRT observations
  71. HAWC Burst Alert 1008846_957: Konus-Wind observations
  72. GRB 190804B: Swift-XRT afterglow detection
  73. Alert from the HAWC Burst Monitor
  74. GRB 190805B: Swift-XRT observations
  75. GRB 190805B: Fermi GBM detection
  76. GRB 190804B: Swift-XRT observations
  77. GRB 190731A: Swift-XRT afterglow detection
  78. GRB 190731A: Fermi GBM detection
  79. GRB190731A: Fermi-LAT detection
  80. Fermi-LAT Gamma-ray Observations of IceCube-190730A
  81. IceCube-190730A - HAWC follow-up
  82. IceCube 190730A: one weakly associated counterpart candidates in INTEGRAL SPI-ACS, and IBIS prompt observation
  83. LIGO/Virgo S190728q: No counterpart candidates in Fermi-LAT observations
  84. LIGO/Virgo S190728q: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  85. GRB 190727B: Fermi-LAT detection
  86. GRB 190727B: Fermi GBM observations
  87. LIGO/Virgo S190727h: No counterpart candidates in Fermi-LAT observations
  88. LIGO/Virgo S190727h: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  89. LIGO/Virgo S190718y: Swift XRT observations, 45 X-ray sources
  90. LIGO/Virgo S190720a: No counterpart candidates in Fermi-LAT observations
  91. GRB 190720A: Fermi GBM detection
  92. GRB 190719C: Fermi GBM detection
  93. GRB 190719C: Swift-XRT refined Analysis
  94. LIGO/Virgo S190720a: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  95. GRB 190719C: NOT candidate optical afterglow and host
  96. LIGO/Virgo S190718y: No counterpart candidates in Fermi-LAT observations
  97. GRB 190718A: Swift-XRT refined Analysis
  98. LIGO/Virgo S190718y: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  99. GRB 190714A: an X-ray flare from 2E 1624.6+1504/UCAC4 525-061488
  100. GRB 190708B: confirmation of the X-ray afterglow

Advanced

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