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').

19119 results found.

  1. EP241119a: GIT optical upper limits
  2. EP241119a : J-band observations with WINTER
  3. EP241119a: EP detection of a fast X-ray transient
  4. GRB 241112B: Mephisto further optical observations
  5. GRB 241030A: J-band observations
  6. GRB 241115a: PRIME near-infrared upper limits
  7. GRB 241117A: Swift/BAT-GUANO localization skymap of a burst
  8. LIGO/Virgo/KAGRA S241116cq: Upper limits from Swift/BAT-GUANO
  9. GRB 241117A: SVOM/GRM observation of a short burst with extended emission
  10. GRB 241115B: Swift/BAT-GUANO localization skymap of a long burst
  11. GRB 241115A: Swift-XRT afterglow detection
  12. LIGO/Virgo/KAGRA S241116cq: Identification of a GW compact binary merger candidate
  13. EP241115a/GRB 241115D: Optical upper limits with Kinder observations
  14. GRB 241115A: Mephisto upper limits
  15. GRB 241113B: Mephisto upper limits
  16. EP241115a/GRB 241115D: Swift/XRT follow-up observation
  17. GRB 241115D / EP 241115a: SVOM/GRM observation
  18. EP241113a: Swift XRT weak detection
  19. GRB 241115A: LCOGT Optical Upper Limits
  20. GRB 241115C: Swift/BAT-GUANO localization skymap of a burst
  21. LIGO/Virgo/KAGRA S241114bi: Updated Sky localization and EM Bright Classification
  22. EP241115a: EP detection of a fast X-ray transient
  23. Swift GRB 241115A: Global MASTER-Net observations report
  24. Fermi GRB 241115A: Global MASTER-Net observations report
  25. GRB 241115A: Swift detection of a burst
  26. EP 241113a: LBT possible optical counterpart
  27. LIGO/Virgo/KAGRA S241114bi: Identification of a GW compact binary merger candidate
  28. GRB 241113A: PRIME near-infrared upper limits
  29. GRB 241113B: J-band upper limit from WINTER
  30. GRB 241113A: J-band observations with WINTER
  31. EP241113a : J-band observations with WINTER
  32. GRB 241030A: LCO optical observation
  33. GRB 241113B: Swift-XRT observations
  34. GRB 241113A: 1.6m Mephisto and 50cm array optical upper limits
  35. EP241113b/GRB 241113B: EP detection of GRB 241113B
  36. LIGO/Virgo/KAGRA S241114y: Identification of a GW compact binary merger candidate
  37. GRB 241113A: Swift/UVOT Detection
  38. GRB 241113A: REM detection of the optical/NIR afterglow
  39. Konus-Wind detection of GRB 241107A (short/hard)
  40. LIGO/Virgo/KAGRA S241113p: Identification of a GW compact binary merger candidate
  41. GRB 241113A: LCO optical observations
  42. GRB 241112B: GMG Optical Upper Limit
  43. GRB 241113A: Enhanced Swift-XRT position
  44. GRB241113A: LCOGT (40-cm) optical counterpart detection
  45. GRB 241113A: Swift detection of a burst with an optical counterpart
  46. SVOM/GRM detection of a short burst from SGR 1E1841-045
  47. Fermi trigger No 753166198: Global MASTER-Net observations report
  48. GRB 241112B: AbAO optical upper limit
  49. GRB 241107A: GROWTH-India telescope optical upper limit
  50. GRB 241112B: Optical afterglow detection confirmation in revisiting the Mephisto data
  51. GRB 241112B: LCO optical detection of the SVOM/VT candidate
  52. GRB 241112B: Mephisto optical upper limits
  53. GRB 241112B: GOTO optical upper limits
  54. GRB 241107A: INTEGRAL IBIS localization
  55. LIGO/Virgo/KAGRA S241109bn: ATLAS observations and discovery of the potential counterpart AT2024aawt
  56. LIGO/Virgo/KAGRA S241111bn: Identification of a GW compact binary merger candidate
  57. IPN triangulation of GRB 241107A (short/hard)
  58. GRB 241025C: VZLUSAT-2 detection
  59. GRB 241025A: VZLUSAT-2 detection
  60. GRB 241018A: cubesat Avion detection
  61. GRB 241030B: TESS detection of optical counterpart
  62. LIGO/Virgo/KAGRA S241110br: Identification of a GW compact binary merger candidate
  63. LIGO/Virgo/KAGRA S241109bn: Upper limits from EP-WXT observations
  64. LIGO/Virgo/KAGRA S241109bn: Coverage and upper limits from MAXI/GSC observations
  65. LIGO/Virgo/KAGRA S241109bn: Updated Sky localization and EM Bright Classification
  66. EP241107a: AbAO optical upper limit
  67. GRB 241108A: Further COLIBRÍ Upper Limits on the Optical Counterpart
  68. LIGO/Virgo/KAGRA S241109bn: Identification of a GW compact binary merger candidate
  69. EP241109a: confirmation of a stellar flare by BOOTES-7
  70. LIGO/Virgo/KAGRA S241109p: Identification of a GW compact binary merger candidate
  71. EP241107a: KAIT optical observations
  72. GRB 241030A: TESS observations
  73. GRB 241108A: COLIBRÍ Upper Limits on the Optical Counterpart
  74. EP241107a: Kinder optical follow-up observations
  75. GRB 241025A: radio detection with the VLA
  76. EP241107a: AKO Optical Afterglow Follow-Up Observations
  77. EP241107a: GSP detects optical counterpart
  78. GRB 241105A: SVOM/GRM observation
  79. EP241107a: OHP/T193 photometric and spectroscopic observations
  80. GRB 241105a: PRIME near-infrared upper limits
  81. GRB 241105A: ePESSTO+ NTT optical afterglow detection
  82. EP241107a: GIT optical observations
  83. EP241107a: SVOM/C-GFT optical observations
  84. EP241107a: AKO Optical Afterglow Detection
  85. GRB 241025A: LBT optical observations
  86. EP241107a: EP on-board trigger and autonomous follow-up observation
  87. GRB 241105A: VLT/FORS2 optical afterglow rapid fading
  88. GRB 241105A: Swift/UVOT Detection
  89. Konus-Wind detection of GRB 241105A (short with extended emission)
  90. GRB 241105A: Swift-XRT afterglow detection
  91. GRB 241104A: Swift-XRT observations
  92. GRB 240511A: LCO upper limits
  93. GRB 241105A: GOTO tentative optical counterpart candidate
  94. GRB 241104A: SVOM/VT optical candidate
  95. GRB 241105A: Fermi GBM Final Real-time Localization
  96. GRB 241104A/EP241104a: Optical upper limits with Kinder observations
  97. GRB 241104A: COLIBRÍ Upper Limits on the Optical Counterpart
  98. EP241104a: EP detection of GRB 241104A X-ray emission
  99. GRB 241010A: host galaxy redshift z = 0.977
  100. EP241101a NUTTelA-TAO / BSTI Measurements 2024-11-02

Advanced

Download all Circulars as a .tar.gz archive:
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