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"

24645 results found.

  1. GRB 241113A: Swift/UVOT Detection
  2. GRB 241113A: REM detection of the optical/NIR afterglow
  3. LIGO/Virgo/KAGRA S241113p: Identification of a GW compact binary merger candidate
  4. GRB 241113A: LCO optical observations
  5. GRB 241112B: GMG Optical Upper Limit
  6. GRB 241113A: Enhanced Swift-XRT position
  7. GRB241113A: LCOGT (40-cm) optical counterpart detection
  8. GRB 241113A: Swift detection of a burst with an optical counterpart
  9. SVOM/GRM detection of a short burst from SGR 1E1841-045
  10. LIGO/Virgo/KAGRA S241111bn: Updated Sky localization
  11. GRB 241112B: AbAO optical upper limit
  12. GRB 241107A: GROWTH-India telescope optical upper limit
  13. Fermi-GBM Sub-Threshold Detection of GRB 241112B
  14. GRB 241112B: Optical afterglow detection confirmation in revisiting the Mephisto data
  15. GRB 241112B: Swift-XRT afterglow detection
  16. GRB 241112B: LCO optical detection of the SVOM/VT candidate
  17. GRB 241112B: Mephisto optical upper limits
  18. GRB 241112B: GOTO optical upper limits
  19. GRB 241107A: INTEGRAL IBIS localization
  20. LIGO/Virgo/KAGRA S241110br: NED Galaxies in the Localization Volume
  21. LIGO/Virgo/KAGRA S241109bn: ATLAS observations and discovery of the potential counterpart AT2024aawt
  22. GRB 241105A: VLT/FORS2 refined spectroscopic redshift z = 2.681
  23. LIGO/Virgo/KAGRA S241111bn: Identification of a GW compact binary merger candidate
  24. IPN triangulation of GRB 241107A (short/hard)
  25. GRB 241025C: VZLUSAT-2 detection
  26. GRB 241025A: VZLUSAT-2 detection
  27. GRB 241018A: cubesat Avion detection
  28. GRB 241030B: TESS detection of optical counterpart
  29. LIGO/Virgo/KAGRA S241110br: Updated Sky localization
  30. LIGO/Virgo/KAGRA S241110bk: 1 counterpart neutrino candidate event from an IceCube neutrino search
  31. LIGO/Virgo/KAGRA S241110br: Identification of a GW compact binary merger candidate
  32. LIGO/Virgo/KAGRA S241109bn: Upper limits from EP-WXT observations
  33. Integral GRB241109.89: Global MASTER-Net observations report
  34. LIGO/Virgo/KAGRA S241109bn: Coverage and upper limits from MAXI/GSC observations
  35. LIGO/Virgo/KAGRA S241109bn: Updated Sky localization and EM Bright Classification
  36. EP241107a: AbAO optical upper limit
  37. LIGO/Virgo/KAGRA S241109bn: Upper limits from Fermi-GBM Observations
  38. GRB 241108A: Further COLIBRÍ Upper Limits on the Optical Counterpart
  39. LIGO/Virgo/KAGRA S241109p: Updated Sky localization and Source Classification
  40. LIGO/Virgo/KAGRA S241109bn: Identification of a GW compact binary merger candidate
  41. EP241109a: confirmation of a stellar flare by BOOTES-7
  42. GRB 241108A: Swift-XRT observations
  43. LIGO/Virgo/KAGRA S241109p: Identification of a GW compact binary merger candidate
  44. EP241107a: KAIT optical observations
  45. GRB 241030A: TESS observations
  46. GRB 241108A: COLIBRÍ Upper Limits on the Optical Counterpart
  47. EP241107a: Kinder optical follow-up observations
  48. GRB 241025A: radio detection with the VLA
  49. EP241107a: AKO Optical Afterglow Follow-Up Observations
  50. EP241107a: GSP detects optical counterpart
  51. GRB 241105A: SVOM/GRM observation
  52. EP241107a: OHP/T193 photometric and spectroscopic observations
  53. GRB 241105a: PRIME near-infrared upper limits
  54. GRB 241105A: ePESSTO+ NTT optical afterglow detection
  55. EP241107a: GIT optical observations
  56. EP241107a: SVOM/C-GFT optical observations
  57. EP241107a: AKO Optical Afterglow Detection
  58. GRB 241025A: LBT optical observations
  59. GRB 241105A: VLT/FORS2 optical afterglow rapid fading
  60. GRB 241105A: Swift/UVOT Detection
  61. GRB 241105A: Fermi GBM Observation of a Short Burst with Extended Emission
  62. LIGO/Virgo/KAGRA S241106ba: 1 counterpart neutrino candidate event from an IceCube neutrino search
  63. LIGO/Virgo/KAGRA S241102o: 1 counterpart neutrino candidate event from an IceCube neutrino search
  64. GRB 241105A: Swift-XRT afterglow detection
  65. GRB 241105A: VLT/FORS2 spectroscopic redshift z = 2.681
  66. GRB 241104A: Swift-XRT observations
  67. GRB 240511A: LCO upper limits
  68. GRB 241104A: Fermi GBM Observation
  69. GRB 241105A: Swift/BAT-GUANO arcminute localization of a short burst
  70. GRB 241104A: SVOM/VT optical candidate
  71. GRB 241104A/EP241104a: Optical upper limits with Kinder observations
  72. GRB 241104A: COLIBRÍ Upper Limits on the Optical Counterpart
  73. EP241104a: EP detection of GRB 241104A X-ray emission
  74. GRB 241010A: host galaxy redshift z = 0.977
  75. EP241101a NUTTelA-TAO / BSTI Measurements 2024-11-02
  76. GRB 240821A: further radio observations with the VLA
  77. EP241103a: GIT optical upper limit
  78. EP241021a: OHP/T193 further optical observations
  79. LIGO/Virgo/KAGRA S241102br: OHP/T193 optical observations
  80. LIGO/Virgo/KAGRA S241102cy: Updated Sky localization
  81. LIGO/Virgo/KAGRA S241102br: Updated Sky localization
  82. EP241103a: Swift XRT detection and improved X-ray position
  83. EP241021a: continued SOAR observations
  84. EP241101a: Optical upper limits with Kinder observations
  85. EP241101a: OHP/T193 optical observations
  86. LIGO/Virgo/KAGRA S241102br: MASTER observations and OT detection
  87. LIGO/Virgo/KAGRA S241102br: EP-WXT X-ray follow-up and flux limits
  88. GRB 241030A: Swift-UVOT observations of the optical prompt flare
  89. EP241103a: GSP optical upper limit
  90. EP241103A: LCO optical observations
  91. EP241103a: an X-ray transient detected by Einstein Probe
  92. LIGO/Virgo/KAGRA S241101ee: Updated Sky localization
  93. S241102cy: Identification of a GW compact binary merger candidate
  94. LIGO/Virgo/KAGRA S241102br: NED Galaxies in the Localization Volume
  95. LIGO/Virgo/KAGRA S241102br: Identification of a GW compact binary merger candidate
  96. Kinder optical follow-up observations of EP241021a, EP241026b, and EP241030a/GRB241030A
  97. GRB241030A: OHP/T193 optical observations
  98. GRB 241101A: FRAM-ORM optical limit
  99. LIGO/Virgo/KAGRA S241101ee: Identification of a GW compact binary merger candidate
  100. GRB 241030A/EP241030a: TNOT observations of the optical counterpart

Advanced

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