Skip to main content
GCN at AAS 245, Legacy Circulars Address Retirement. 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').
  1. GRB 241113A: 1.6m Mephisto and 50cm array optical upper limits
  2. GRB 241113A: KAIT optical observations
  3. EP241113b: Global MASTER-Net observations report
  4. EP241113b/GRB 241113B: EP detection of GRB 241113B
  5. Fermi-LAT gamma-ray observations of IceCube-241113A
  6. GRB 241113B: SVOM/GRM observation
  7. EP241113a: EP on-board trigger and autonomous follow-up observation
  8. LIGO/Virgo/KAGRA S241114y: Identification of a GW compact binary merger candidate
  9. GRB 241113A: Swift-XRT refined Analysis
  10. EP241107a: SOAR upper limits
  11. GRB 241113A: Swift/UVOT Detection
  12. GRB 241113A: REM detection of the optical/NIR afterglow
  13. Konus-Wind detection of GRB 241107A (short/hard)
  14. LIGO/Virgo/KAGRA S241113p: Identification of a GW compact binary merger candidate
  15. Fermi Gamma-ray Burst Monitor trigger 753166198/241113201 is not a GRB
  16. GRB 241113B: Swift ToO observations
  17. GRB 241113A: LCO optical observations
  18. IceCube-241113A - IceCube observation of a high-energy neutrino candidate track-like event
  19. GRB 241112B: GMG Optical Upper Limit
  20. GRB 241113A: Enhanced Swift-XRT position
  21. GRB241113A: LCOGT (40-cm) optical counterpart detection
  22. GRB 241113B : detection of a long GRB by SVOM/ECLAIRs
  23. GRB 241113A: MASTER010615.66-224018.2 optical counterpart detection
  24. GRB 241113A: Swift detection of a burst with an optical counterpart
  25. Swift GRB241113.33: Global MASTER-Net observations report
  26. SVOM/GRM detection of a short burst from SGR 1E1841-045
  27. Fermi trigger No 753166198: Global MASTER-Net observations report
  28. LIGO/Virgo/KAGRA S241111bn: Updated Sky localization
  29. GRB 241105A: ATCA Radio Upper Limits
  30. GRB 241112B: AbAO optical upper limit
  31. GRB 241107A: GROWTH-India telescope optical upper limit
  32. IceCube Alert 241113.02: Global MASTER-Net observations report
  33. Fermi GRB 241112A: Global MASTER-Net observations report
  34. Fermi-GBM Sub-Threshold Detection of GRB 241112B
  35. GRB 241112B: Optical afterglow detection confirmation in revisiting the Mephisto data
  36. GRB 241112B: Swift-XRT afterglow detection
  37. GRB 241112B: LCO optical detection of the SVOM/VT candidate
  38. GRB 241112B: SVOM/GRM observation
  39. GRB 241112B: SVOM/VT afterglow detection
  40. Fermi Gamma-ray Burst Monitor trigger 752995908/241111230 (GRB 241111A) is not a GRB
  41. GRB 241107A: Swift/BAT candidate arcminute localization of a short burst
  42. GRB 241112B: Mephisto optical upper limits
  43. GRB 241112B: GOTO optical upper limits
  44. GRB 241112B: Swift ToO observations
  45. GRB 241112B : detection of a long GRB by SVOM/ECLAIRs
  46. GRB 241107A: INTEGRAL IBIS localization
  47. EP241107a: EP-FXT follow-up observations
  48. GRB 241112A: Fermi GBM Final Real-time Localization
  49. LIGO/Virgo/KAGRA S241110br: NED Galaxies in the Localization Volume
  50. LIGO/Virgo/KAGRA S241109bn: ATLAS observations and discovery of the potential counterpart AT2024aawt
  51. GRB 241105A: VLT/FORS2 refined spectroscopic redshift z = 2.681
  52. LIGO/Virgo/KAGRA S241111bn: Identification of a GW compact binary merger candidate
  53. IPN triangulation of GRB 241107A (short/hard)
  54. GRB 241107A: INTEGRAL/IBIS/PICsIT detection of a short burst
  55. GRB 241025C: VZLUSAT-2 detection
  56. GRB 241025A: VZLUSAT-2 detection
  57. GRB 241018A: cubesat Avion detection
  58. Fermi trigger No 752990530: Global MASTER-Net observations report
  59. GRB 241111A: Fermi GBM Final Real-time Localization
  60. GRB 241030B: TESS detection of optical counterpart
  61. LIGO/Virgo/KAGRA S241110br: Updated Sky localization
  62. LIGO/Virgo/KAGRA S241110bk: 1 counterpart neutrino candidate event from an IceCube neutrino search
  63. LIGO/Virgo/KAGRA S241110br: Identification of a GW compact binary merger candidate
  64. LIGO/Virgo/KAGRA S241109bn: Upper limits from EP-WXT observations
  65. Fermi trigger No 752878030: Global MASTER-Net observations report
  66. Integral GRB241109.89: Global MASTER-Net observations report
  67. LIGO/Virgo/KAGRA S241109bn: Coverage and upper limits from MAXI/GSC observations
  68. EP241109a: KAIT photometry and 3 m Shane spectroscopy from Lick observatory
  69. LIGO/Virgo/KAGRA S241109bn: Updated Sky localization and EM Bright Classification
  70. INTEGRAL detection of a burst from 1E 1841-045
  71. EP241107a: AbAO optical upper limit
  72. LIGO/Virgo/KAGRA S241109bn: Upper limits from Fermi-GBM Observations
  73. GRB 241108A: Further COLIBRÍ Upper Limits on the Optical Counterpart
  74. LIGO/Virgo/KAGRA S241109p: Updated Sky localization and Source Classification
  75. LIGO/Virgo/KAGRA S241109bn: Global MASTER-Net observations report
  76. LIGO/Virgo/KAGRA S241109bn: Identification of a GW compact binary merger candidate
  77. EP241109a: confirmation of a stellar flare by BOOTES-7
  78. EP241109a: EP on-board trigger and autonomous follow-up observation
  79. GRB 241108A: Swift-XRT observations
  80. LIGO/Virgo/KAGRA S241109p: Identification of a GW compact binary merger candidate
  81. EP241107A: MASTER optical observations of xray transient
  82. EP241107a: KAIT optical observations
  83. GRB 241108A: Swift ToO observations
  84. GRB 241030A: TESS observations
  85. GRB 241108A: COLIBRÍ Upper Limits on the Optical Counterpart
  86. GRB 241108A : a likely weak long GRB detected by SVOM/ECLAIRs
  87. EP241107a: Kinder optical follow-up observations
  88. GRB 241025A: radio detection with the VLA
  89. GRB 241104A: CALET Gamma-Ray Burst Monitor detection
  90. EP241107a: AKO Optical Afterglow Follow-Up Observations
  91. EP241107a: GSP detects optical counterpart
  92. EP241107a: Gemini-South spectroscopic confirmation (z = 0.456)
  93. GRB 241107A: SVOM/GRM detection of a short burst
  94. GRB 241105A: EP-FXT follow-up observations
  95. GRB 241105A: SVOM/GRM observation
  96. EP241107a: OHP/T193 photometric and spectroscopic observations
  97. GRB 241105a: PRIME near-infrared upper limits
  98. EP241107a: FTW Optical and NIR observations of the optical counterpart
  99. GRB 241105A: ePESSTO+ NTT optical afterglow detection
  100. EP241107a: GIT optical observations

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