Skip to main content
End of Swift Science Operations, CHIME Notices Unavailable During Upgrade. See news and announcements

GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"

23606 results found.

  1. GRB 241120A: Mondy and AbAO optical observations
  2. EP241119a: Optical upper limits with Kinder observations
  3. EP trigger ID 01709122294: the X-ray transient is likely a stellar flare event
  4. EP241119a: GIT optical upper limits
  5. EP241119a : J-band observations with WINTER
  6. EP241119a: EP detection of a fast X-ray transient
  7. GRB 241112B: Mephisto further optical observations
  8. GRB 241030A: J-band observations
  9. GRB 241115a: PRIME near-infrared upper limits
  10. GRB 241117A: Swift/BAT-GUANO localization skymap of a burst
  11. Fermi GRB 241118A: Global MASTER-Net observations report
  12. GRB 241117A: SVOM/GRM observation of a short burst with extended emission
  13. GRB 241115B: Swift/BAT-GUANO localization skymap of a long burst
  14. GRB 241115A: Swift-XRT afterglow detection
  15. LIGO/Virgo/KAGRA S241116cq: Identification of a GW compact binary merger candidate
  16. EP241115a/GRB 241115D: Optical upper limits with Kinder observations
  17. GRB 241115A: Mephisto upper limits
  18. GRB 241113B: Mephisto upper limits
  19. EP241115a/GRB 241115D: Swift/XRT follow-up observation
  20. GRB 241115D / EP 241115a: SVOM/GRM observation
  21. The EP-WXT trigger 01709120856 is likely a flaring star
  22. EP241113a: Swift XRT weak detection
  23. GRB 241115A: LCOGT Optical Upper Limits
  24. GRB 241115C: Swift/BAT-GUANO localization skymap of a burst
  25. LIGO/Virgo/KAGRA S241114bi: Updated Sky localization and EM Bright Classification
  26. EP241115a: EP detection of a fast X-ray transient
  27. GRB 241115A: Swift detection of a burst
  28. EP 241113a: LBT possible optical counterpart
  29. LIGO/Virgo/KAGRA S241114bi: Upper limits from Fermi-GBM Observations
  30. LIGO/Virgo/KAGRA S241114bi: Identification of a GW compact binary merger candidate
  31. GRB 241113A: PRIME near-infrared upper limits
  32. GRB 241113B: J-band upper limit from WINTER
  33. GRB 241113A: J-band observations with WINTER
  34. EP241113a : J-band observations with WINTER
  35. GRB 241030A: LCO optical observation
  36. GRB 241113B: Swift-XRT observations
  37. GRB 241113A: 1.6m Mephisto and 50cm array optical upper limits
  38. EP241113b/GRB 241113B: EP detection of GRB 241113B
  39. LIGO/Virgo/KAGRA S241114y: Identification of a GW compact binary merger candidate
  40. GRB 241113A: Swift-XRT refined Analysis
  41. GRB 241113A: Swift/UVOT Detection
  42. GRB 241113A: REM detection of the optical/NIR afterglow
  43. Konus-Wind detection of GRB 241107A (short/hard)
  44. LIGO/Virgo/KAGRA S241113p: Identification of a GW compact binary merger candidate
  45. GRB 241113A: LCO optical observations
  46. GRB 241112B: GMG Optical Upper Limit
  47. GRB 241113A: Enhanced Swift-XRT position
  48. GRB241113A: LCOGT (40-cm) optical counterpart detection
  49. GRB 241113A: Swift detection of a burst with an optical counterpart
  50. SVOM/GRM detection of a short burst from SGR 1E1841-045
  51. GRB 241105A: ATCA Radio Upper Limits
  52. GRB 241112B: AbAO optical upper limit
  53. GRB 241107A: GROWTH-India telescope optical upper limit
  54. GRB 241112B: Optical afterglow detection confirmation in revisiting the Mephisto data
  55. GRB 241112B: Swift-XRT afterglow detection
  56. GRB 241112B: LCO optical detection of the SVOM/VT candidate
  57. GRB 241107A: Swift/BAT candidate arcminute localization of a short burst
  58. GRB 241112B: Mephisto optical upper limits
  59. GRB 241112B: GOTO optical upper limits
  60. GRB 241107A: INTEGRAL IBIS localization
  61. LIGO/Virgo/KAGRA S241109bn: ATLAS observations and discovery of the potential counterpart AT2024aawt
  62. LIGO/Virgo/KAGRA S241111bn: Identification of a GW compact binary merger candidate
  63. IPN triangulation of GRB 241107A (short/hard)
  64. GRB 241018A: cubesat Avion detection
  65. GRB 241030B: TESS detection of optical counterpart
  66. LIGO/Virgo/KAGRA S241110bk: 1 counterpart neutrino candidate event from an IceCube neutrino search
  67. LIGO/Virgo/KAGRA S241110br: Identification of a GW compact binary merger candidate
  68. LIGO/Virgo/KAGRA S241109bn: Upper limits from EP-WXT observations
  69. LIGO/Virgo/KAGRA S241109bn: Coverage and upper limits from MAXI/GSC observations
  70. EP241109a: KAIT photometry and 3 m Shane spectroscopy from Lick observatory
  71. LIGO/Virgo/KAGRA S241109bn: Updated Sky localization and EM Bright Classification
  72. EP241107a: AbAO optical upper limit
  73. LIGO/Virgo/KAGRA S241109bn: Upper limits from Fermi-GBM Observations
  74. GRB 241108A: Further COLIBRÍ Upper Limits on the Optical Counterpart
  75. LIGO/Virgo/KAGRA S241109bn: Identification of a GW compact binary merger candidate
  76. GRB 241108A: Swift-XRT observations
  77. LIGO/Virgo/KAGRA S241109p: Identification of a GW compact binary merger candidate
  78. EP241107a: KAIT optical observations
  79. GRB 241030A: TESS observations
  80. GRB 241108A: COLIBRÍ Upper Limits on the Optical Counterpart
  81. EP241107a: Kinder optical follow-up observations
  82. GRB 241025A: radio detection with the VLA
  83. EP241107a: AKO Optical Afterglow Follow-Up Observations
  84. EP241107a: Gemini-South spectroscopic confirmation (z = 0.456)
  85. GRB 241105A: SVOM/GRM observation
  86. EP241107a: OHP/T193 photometric and spectroscopic observations
  87. GRB 241105a: PRIME near-infrared upper limits
  88. GRB 241105A: ePESSTO+ NTT optical afterglow detection
  89. EP241107a: GIT optical observations
  90. EP241107a: SVOM/C-GFT optical observations
  91. EP241107a: AKO Optical Afterglow Detection
  92. GRB 241025A: LBT optical observations
  93. GRB 241105A: VLT/FORS2 optical afterglow rapid fading
  94. GRB 241105A: Swift/UVOT Detection
  95. EP241101a: CrAO ZTSH optical observations
  96. GRB 241105A: Fermi GBM Observation of a Short Burst with Extended Emission
  97. LIGO/Virgo/KAGRA S241106ba: 1 counterpart neutrino candidate event from an IceCube neutrino search
  98. LIGO/Virgo/KAGRA S241102o: 1 counterpart neutrino candidate event from an IceCube neutrino search
  99. GRB 241105A: Swift-XRT afterglow detection
  100. GRB 241104A: Swift-XRT observations

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