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"

32494 results found.

  1. EP trigger ID 01709059262: Lick/Kast spectroscopy with 3 m Shane telescope
  2. NuEm-240926A / IC240926A: BZQJ0955+4532 ~0.6m optical decay and rebrightening detection by MASTER
  3. Konus-Wind detection of GRB 240905B
  4. GRB 240529A: FRAM-ORM early optical afterglow observations reveal plateau and rebrightening
  5. EP240919a / GRB 240919A: SVOM/VT upper limit
  6. EP240918b and EP240918c: EP-FXT follow-up observations
  7. LIGO/Virgo/KAGRA S240925n: Updated Sky localization and Source Classification
  8. Insight-HXMT ToO observations of X-ray bursts from SGR 1E 1841-045 / Kes 73
  9. GRB 240716A: Swift/BAT-GUANO localization skymap of a long burst
  10. LIGO/Virgo/KAGRA S240925n: Identification of a GW compact binary merger candidate
  11. Konus-Wind detection of GRB 240918B
  12. IPN triangulation of GRB 240918B
  13. GRB 240905B: VZLUSAT-2 detection
  14. LIGO/Virgo/KAGRA S240922df: Updated Sky localization
  15. LIGO/Virgo/KAGRA S240920dw: Updated Sky localization
  16. LIGO/Virgo/KAGRA S240921cw: Updated Sky localization
  17. LIGO/Virgo/KAGRA S240924a: Updated Sky localization
  18. LIGO/Virgo/KAGRA S240920bz: Updated Sky localization and Source Classification
  19. LIGO/Virgo/KAGRA S240923ct: Updated Sky localization and Source Classification
  20. EP trigger ID 01709059262: correction to the observation start time and source localization
  21. LIGO/Virgo/KAGRA S240924a: Identification of a GW compact binary merger candidate
  22. LIGO/Virgo/KAGRA S240923ct: Identification of a GW compact binary merger candidate
  23. LIGO/Virgo S240919bn: GOTO optical upper limits
  24. GRB 240918B: AstroSat CZTI detection
  25. LIGO/Virgo/KAGRA S240922df: Identification of a GW compact binary merger candidate
  26. LIGO/Virgo/KAGRA S240921cw: Identification of a GW compact binary merger candidate
  27. EP240919a: EP-FXT follow-up observation update
  28. EP240913A/GRB 240913C: AbAO optical upper limit
  29. EP240919a / GRB 240919A: Mondy optical upper limit
  30. EP240913a/GRB 240913C: 1.6m Mephisto observations
  31. EP240918a: SVOM/VT upper limit
  32. Fermi GBM Sub-Threshold Detection of GRB240919A / EP240919a
  33. EP240919a / GRB 240919A: REM optical and NIR upper limits
  34. EP240919a / GRB 240919A: KAIT optical upper limit
  35. EP240918b and EP240918c: Optical upper limits with Kinder observations
  36. GRB 240414A: further radio observations with the VLA
  37. EP240919a: Optical upper limit with Kinder observations
  38. GRB 240919A / EP240919a: SVOM/GRM observation
  39. EP240919a: INTEGRAL SPI-ACS confirmation of reported high-energy counterpart
  40. EP240919a: INTEGRAL SPI-ACS confirmation of reported high-energy counterpart
  41. LIGO/Virgo/KAGRA S240920dw: Identification of a GW compact binary merger candidate
  42. EP EP240919a: Global MASTER-Net observations report
  43. GRB 240910A: radio detection with the VLA
  44. EP240918a: 1.6m Mephisto multi-band Optical Upper Limit
  45. EP240919a: NOT and Gemini optical observations
  46. EP240919a: GOTO optical upper limits
  47. EP240919a: JinShan optical upper limits
  48. EP240919a is likely a GRB event (duplicate submission of 37563)
  49. EP240919a is likely a GRB event
  50. LIGO/Virgo/KAGRA S240920bz: Identification of a GW compact binary merger candidate
  51. GRB 240918A and GRB 240918B : INTEGRAL SPI ACS LIGHT CURVE
  52. LIGO/Virgo/KAGRA S240919bn: Updated Sky localization
  53. GRB 240918B: Fermi GBM Detection
  54. LIGO/Virgo/KAGRA S240917cb: Updated Sky localization and EM Bright Classification
  55. LIGO/Virgo/KAGRA S240916ar: Updated Sky localization and EM Bright Classification
  56. EP240918a: EP observation update
  57. GRB 240910A: further Swift observations and confirmation of afterglow
  58. LIGO/Virgo/KAGRA S240919bn: Identification of a GW compact binary merger candidate
  59. EP240918a: Swift-XRT observation
  60. Fermi GRB 240918A: Global MASTER-Net observations report
  61. EP EP240918a: Global MASTER-Net observations report
  62. EP240918a: JinShan optical upper limits
  63. EP240918a: YAHPT Optical Upper Limit
  64. EP240918a: Optical upper limits with Kinder observations
  65. EP240918a: GMG Optical Upper Limit
  66. GRB 240916A: GRBAlpha detection
  67. GRB 240914B: GRBAlpha detection
  68. GRB 240916A: NOT optical observation
  69. GRB 240912A: Swift-BAT refined analysis
  70. IPN triangulation of GRB 240913C / EP 240913a
  71. GRB 240825A: INTEGRAL SPI ACS LIGHT CURVE
  72. GRB 240825A: The nature of the afterglow motivates the search of the associated supernova
  73. GRB 240916A: Fermi GBM Observation
  74. LIGO/Virgo/KAGRA S240917cb: Identification of a GW compact binary merger candidate
  75. GRB 240821A: radio observation with the VLA
  76. GRB 240916A (AT 2024vlp / GOTO24fzn): VLT/X-shooter redshift
  77. GRB 240916A: Swift-XRT afterglow detection
  78. LIGO/Virgo/KAGRA S240916ar: Identification of a GW compact binary merger candidate
  79. GRB 240916A: Swift ToO observations
  80. GRB 240916A: JinShan optical decay in one of the two GOTO candidates
  81. GRB 240916A: GOTO identification of two new optical sources within the GBM localisation region
  82. EP EP240913a: Global MASTER-Net observations report
  83. LIGO/Virgo/KAGRA S240915b: Coverage and upper limits from MAXI/GSC observations
  84. GRB 240916A INTEGRAL SPI ACS LIGHT CURVE
  85. LIGO/Virgo/KAGRA S240915bd: Updated Sky localization
  86. EP240913a: VLT/HAWK-I near-infrared upper limits
  87. LIGO/Virgo/KAGRA S240915bd: Identification of a GW compact binary merger candidate
  88. LIGO/Virgo/KAGRA S240915b: Updated Sky localization and EM Bright Classification
  89. LIGO/Virgo/KAGRA S240915b: Identification of a GW compact binary merger candidate
  90. EP240913a/GRB 240913C: KAIT optical upper limit
  91. EP240913a / GRB 240913C INTEGRAL SPI ACS LIGHT CURVE
  92. GRB 240913C: Fermi GBM detection
  93. GRB 240913C: Joint location by ETJASMIN
  94. GRB 240914B: AstroSat CZTI detection
  95. EP240913A / GRB 240913C: AstroSat CZTI detection
  96. GRB 240914A: SVOM/GRM observation
  97. GRB 240910A: SVOM/VT optical observations
  98. GRB 240914A: Swift ToO observations
  99. EP240913a: NOT optical upper limits
  100. EP240913a: JinShan optical upper limits

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