Skip to main content
JSON Notices via Email, Kafka Cron Jobs, Submitter Profile, GCN is Hiring. 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"

20502 results found.

  1. EP251122a: Einstein Probe detection of an X-ray transient
  2. EP251118a: Continued Optical Detection with Kinder observations
  3. LIGO/Virgo/KAGRA S251105aj: SVOM/ECLAIRs detection of a high-energy transient SVOM J2320.0-2901 through targeted search
  4. GRB 251121A: Swift/BAT-GUANO localization skymap of a short burst
  5. EP251118a: Xinglong-2.16m optical observation
  6. EP251118A: 1.3m DFOT optical afterglow detection
  7. GRB 251118A: Swift/UVOT Detection
  8. EP251118a / GRB 251118C: SAO RAS optical observations
  9. GRB 251118A: Swift-XRT afterglow detection
  10. GRB 251103A: SVOM/ECLAIRs and SVOM/GRM joint refined analysis
  11. EP251118a: Optical detection with Kinder observations
  12. LIGO/Virgo/KAGRA S251112cm: SVOM/VT optical observations and preliminary results
  13. EP251118a / GRB 251118C: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 1-m telescope at CTIO
  14. GRB 251118C: Swift/BAT rates detection of a burst with a possible association with EP 251118A
  15. EP251118A / GRB 251118C : MASTER optical counterpart observations
  16. GRB 251118C: SVOM/GRM observation of a possible gamma-ray counterpart of EP251118a
  17. GRB 251119A: SVOM trigger sb25111901 is not a GRB
  18. EP251118a: VLT near-infrared observation
  19. GRB 251116D: SVOM/GRM observation of a long GRB
  20. GRB 251119A: SVOM detection of a possible burst
  21. EP251118a: NOT spectroscopic redshift of z = 1.216
  22. EP251118a: NOT candidate optical counterpart
  23. EP251118a: Einstein Probe detected of a fast X-ray transient
  24. LIGO/Virgo/KAGRA S251112cm: Upper limits from Glowbug gamma-ray observations
  25. GRB 251116C: SVOM/ECLAIRs refined analysis
  26. GRB 251116B: SVOM/ECLAIRs refined analysis
  27. GRB 251115A: Swift-XRT observations
  28. GRB 251117A: Swift/BAT-GUANO localization skymap of a short burst
  29. GRB 251117A: SVOM/GRM observation of a short burst
  30. GRB 251117A: Fermi-LAT detection
  31. LIGO/Virgo/KAGRA S251117dq: Identification of a GW compact binary merger candidate
  32. LIGO/Virgo/KAGRA S251112cm: J-GEM follow-up observations
  33. LIGO/Virgo/KAGRA S251112cm: WFST follow-up observations and preliminary results
  34. EP251023a: Assy AZT-20 optical observations
  35. EP251023a: UAFO and AbAO optical observations
  36. The EP-WXT trigger 01709247588: more evidence of flaring star from Mondy optical observations
  37. GRB 251025B: further Mondy optical observations
  38. GRB 251111A: Mondy optical upper limit
  39. LIGO/Virgo/KAGRA S251116en: Identification of a GW compact binary merger candidate
  40. LIGO/Virgo/KAGRA S251112cm: Observations with the NSF-DOE Vera C. Rubin Observatory
  41. GRB 251116B: LCO optical upper limits
  42. GRB 251116C: LCO optical upper limits
  43. IceCube-Cascade 251112A: Upper limits from a search for additional neutrino events in IceCube
  44. LIGO/Virgo/KAGRA S251112cm: GRANDMA observations of the skymap
  45. GRB 251013C: joint SVOM/ECLAIRs-GRM refined analysis
  46. LIGO/Virgo/KAGRA S251112cm: NED Galaxies in the 4-Update Localization Volume
  47. LIGO/Virgo/KAGRA S251112cm: DECam GW-MMADS candidates
  48. LIGO/Virgo/KAGRA S251112cm: Updated Sky localization and false alarm rate estimate
  49. GRB 251113A: AstroSat CZTI detection
  50. LIGO/Virgo/KAGRA S251112cm: ATLAS targeted observations of the skymap
  51. LIGO/Virgo/KAGRA S251112cm: Swift XRT observations, 20 X-ray sources
  52. The EP-WXT trigger 01709248221 is likely a flaring star
  53. LIGO/Virgo/KAGRA S251112cm: FTW observations of galaxies within localization region
  54. GRB 251111A: SVOM/ECLAIRs refined analysis
  55. GRB 251025B: SVOM/ECLAIRs refined analysis
  56. GRB 251112A: Swift/UVOT Upper Limits
  57. GRB 251108C: AstroSat CZTI detection
  58. LIGO/Virgo/KAGRA S251112cm: Coverage and upper limits from MAXI/GSC observations
  59. Swift Trigger 1413695: a possible GRB 251112A
  60. GRB251111A: 1.3m DFOT optical upper limit
  61. GRB 251111A: Swift-XRT afterglow detection
  62. GRB 251111A: SVOM/VT optical observations with X-band data
  63. GRB 251111A: SVOM/VT optical observations with VHF data
  64. GRB 251111A: LCO optical observation
  65. GRB 251111A: SVOM/COLIBRÍ (FM-GFT) optical counterpart detection
  66. GRB 251106A: Swift/UVOT Upper Limits
  67. LIGO/Virgo/KAGRA S251108fi: DDOTI Optical Candidate
  68. LIGO/Virgo/KAGRA S251108fi: One counterpart neutrino candidate from IceCube neutrino searches
  69. IceCube-Cascade 251107A: Upper limits from a search for additional neutrino events in IceCube
  70. LIGO/Virgo/KAGRA S251108fi: Identification of a GW compact binary merger candidate
  71. GRB 251102B: SVOM/GRM observation
  72. LIGO/Virgo/KAGRA S251108dn: Identification of a GW compact binary merger candidate
  73. The EP-WXT trigger 01709248051 is likely a flaring star
  74. GRB 251106A: SVOM/COLIBRÍ (FM-GFT) fading of the optical counterpart
  75. GRB 251106A: Swift-XRT afterglow detection
  76. GRB 251106A: Kilonova-Catcher optical upper limit
  77. GRB 251106A: SVOM/COLIBRÍ (FM-GFT) detection of a likely optical counterpart
  78. GRB 251106A: MASTER optical observations
  79. GRB 251103B: AstroSat CZTI detection
  80. EP251102a: Xinglong 2.16-m clear-band observations of the optical counterpart
  81. GRB 251105A: Swift/BAT-GUANO localization skymap of a burst
  82. GRB 251104A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  83. GRB 251023A: SVOM/ECLAIRs detection of a burst through targeted search
  84. GRB 251103B: Swift/UVOT Upper Limits
  85. LIGO/Virgo/KAGRA S251105aj: Identification of a GW compact binary merger candidate
  86. GRB 251103A: WFST optical observations
  87. GRB 251103A: OHP/T193 optical observations
  88. GRB 251103A: Xinglong 2.16m optical detection
  89. GRB 251103A: KAIT optical observations
  90. GRB 251103B: Nanshan/HMT optical upper limit
  91. GRB 251013C: 7DT detection and Medium-band SED of Afterglow
  92. GRB 251103B: MITSuME Akeno optical upper limits
  93. LIGO/Virgo/KAGRA S251103f: Identification of a GW compact binary merger candidate
  94. EP251102a: NIR observations with WINTER
  95. GRB 251103A: J-band detection with WINTER
  96. GRB 251103B: GROWTH-India Telescope optical upper limits
  97. GRB 251103A: Kilonova-Catcher optical afterglow detection
  98. GRB 251103B: Enhanced Swift-XRT position
  99. GRB 251103B: Swift detection of a burst
  100. GRB 251103A: Swift/UVOT Detection

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