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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"

28291 results found.

  1. GRB 250101A: Nanshan/HMT optical observations
  2. GRB 250101A : GIT optical detection
  3. GRB 250101A: GMG Optical Observation
  4. GRB 250101A: Swift detection of a burst with an optical counterpart
  5. LIGO/Virgo/KAGRA S241231du: Coverage and upper limit from MAXI/GSC observations
  6. LIGO/Virgo/KAGRA S250101k: Identification of a GW compact binary merger candidate
  7. GRB 241229B: Continued CrAO ZTSh observations
  8. LIGO/Virgo/KAGRA S241231bg: Updated NED Galaxies in the Localization Volume
  9. LIGO/Virgo/KAGRA S241231bg: Updated Sky localization and EM Bright Classification
  10. LIGO/Virgo/KAGRA S241230ev: Updated Sky localization
  11. LIGO/Virgo/KAGRA S241231bg: NED Galaxies in the Localization Volume
  12. LIGO/Virgo/KAGRA S241230bd: Updated Sky localization
  13. GRB 241228B: Multiband optical monitoring with 1.6m Mephisto
  14. GRB 241229B: SVOM/GRM observation
  15. LIGO/Virgo/KAGRA S241231bg: Identification of a GW compact binary merger candidate
  16. EP241217A: J band upper limit by SYSU 80cm telescope
  17. LIGO/Virgo/KAGRA S241230ev: Identification of a GW compact binary merger candidate
  18. GRB 241229B: SAO RAS optical upper limit
  19. GRB 241228B: SAO RAS optical observations
  20. GRB 241229A: SAO RAS optical observations
  21. IceCube-Cascade 241228A: Upper limits from a search for additional neutrino events in IceCube
  22. GRB 241229A: Swift-XRT observations
  23. EP240702a: 7DT Optical upper limits
  24. GRB 240606B: 7DT Optical upper limits
  25. LIGO/Virgo/KAGRA S241230bd: Identification of a GW compact binary merger candidate
  26. GRB 241229B: Swift-BAT refined analysis
  27. LIGO/Virgo/KAGRA S241225v: Updated Sky localization
  28. LIGO/Virgo/KAGRA S241225c: Updated Sky localization and EM Bright Classification
  29. GRB241229B: UVOT upper limits
  30. GRB 241228B: Fermi GBM Observation
  31. GRB 241228B: Swift-XRT afterglow detection
  32. GRB 241229B: Fermi GBM Observation
  33. GRB 241229B: NUTTelA-TAO / BSTI Optical Limits
  34. GRB 241228A: Mondy optical afterglow observations
  35. GRB 241229A: GOTO optical upper limits
  36. GRB 241228B: VLT/X-shooter redshift of z = 2.674
  37. GRB 241228A: NOT optical upper limits
  38. GRB 241228B: LCO optical observation
  39. GRB 241228A: Swift-BAT refined analysis
  40. GRB 241228B: Swift/BAT-GUANO localization skymap of a burst
  41. GRB 241228A: Fermi GBM Observation
  42. GRB241228B: GROWTH-India Telescope optical observations
  43. GRB 241228B: LCOGT photometry of the likely optical counterpart GOTO24jmz
  44. GRB 241226A: Swift/BAT-GUANO localization skymap of a burst
  45. GRB 241228A: GROWTH-India telescope optical upper limit
  46. GRB 241228B: TRT optical counterpart confirmation
  47. GRB 241228A: Swift-XRT refined Analysis
  48. GRB 241228A: Swift/UVOT Upper Limits
  49. GRB 241228A: Enhanced Swift-XRT position
  50. GRB 241228A: Swift detection of a burst
  51. IceCube-241224A: Upper limits from a search for additional neutrino events in IceCube
  52. LIGO/Virgo/KAGRA S241225c: Two counterpart neutrino candidates from IceCube neutrino searches
  53. GRB 241212A: VZLUSAT-2 detection
  54. EP241223a: Mondy AZT-33IK optical observations
  55. GRB 241029A: LCO optical observation
  56. GRB 241223A: Swift-XRT observations
  57. LIGO/Virgo/KAGRA S241225v: Identification of a GW compact binary merger candidate
  58. GRB 241029A: AbAO AS-32 optical observations
  59. GRB 241223A: Fermi GBM Detection
  60. Fermi trigger No 756678579: Global MASTER-Net observations report
  61. LIGO/Virgo/KAGRA S241225c: Identification of a GW compact binary merger candidate
  62. EP241223a
  63. EP241223a: EP-WXT detection of a fast X-ray transient
  64. EP241113a: Non-detection in Radio Follow-up Observations with eMERLIN
  65. GRB241113A: 7DT Optical upper limits
  66. GRB 241223A: GOTO optical observations summary
  67. GRB 241105A: JWST photometric observations of the host galaxy
  68. EP241217a: e-MERLIN radio observations
  69. GRB 241223A: BALROG localization (Fermi Trigger 756648531 / GRB 241223506)
  70. The EP-WXT trigger 01709129287 is likely a flaring star
  71. EP241217a: Liverpool Telescope optical upper limit
  72. EP241021a: VLA radio detection
  73. GRB 241218A: Mondy AZT-33IK optical upper limit
  74. EP241217a : Leavitt Observatory optical upper limit
  75. GRB 241217A/EP241217b: tentative VLT spectroscopic redshift z=1.879
  76. EP241217a: 1.6m Mephisto multi-band optical observations
  77. GRB 241217a/EP241217B: 1.6m Mephisto optical upper limits
  78. GRB 241218A: Swift/UVOT Upper Limits
  79. EP241217a: optical upper limit with the Liverpool Telescope
  80. GRB 241209B: EP-FXT afterglow detection
  81. GRB 241218A: NOT optical upper limits
  82. GRB 241218A: Swift-BAT refined analysis
  83. GRB 241217A / EP241217B: GRANDMA/T1MPicduMidi optical upperlimits
  84. EP 241217a: NIR detection with P200/WIRC
  85. EP 241217a: Possible J-band detection with WINTER
  86. GRB 241217A/EP241217B: Fermi-GBM Sub-Threshold Detection
  87. EP241217a: refined EP-WXT analysis and EP-FXT follow-up observations
  88. GRB 241217A / EP241217b: Nanshan/HMT optical upper limit
  89. GRB 241217A / EP241217b: NOT optical upper limits
  90. GRB 241218A: REM optical upper limit
  91. GRB 241217A/EP241217b: REM optical/NIR upper limits
  92. EP241217a: REM optical/NIR upper limits
  93. GRB 241217a: Liverpool Telescope optical follow-up
  94. EP241217a: Liverpool Telescope optical follow-up
  95. GRB 241218A: Swift-XRT refined Analysis
  96. EP241217a: NOT optical observations
  97. EP241217a: GROWTH-India Telescope optical observations
  98. GRB 241218A: NUTTelA-TAO / BSTI Optical Limits
  99. EP241119a: 7DT Optical upper limits
  100. EP241217a: Xinglong optical follow-up observations

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