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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"

32766 results found.

  1. LIGO/Virgo S240422ed: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  2. LIGO/Virgo/KAGRA S240422ed: Zwicky Transient Facility observations and candidates
  3. LIGO/Virgo/KAGRA S240422ed: GW-MMADS DECam observations
  4. LIGO/Virgo/KAGRA S240422ed: Magellan Observations
  5. LIGO/Virgo/KAGRA S240422ed: Upper limits from Fermi-GBM Observations
  6. LIGO/Virgo/KAGRA S240422ed: Updated Sky localization and EM Bright Classification
  7. LIGO/Virgo/KAGRA S240422ed: Coverage and upper limits from MAXI/GSC observations
  8. LIGO/Virgo/KAGRA S240422ed: MeerLICHT and BlackGEM observations report
  9. LIGO/Virgo/KAGRA S240422ed: Identification of a GW compact binary merger candidate
  10. GRB 240421A: Glowbug gamma-ray detection
  11. GRB 240414A: radio detection with the VLA
  12. Fermi-LAT gamma-ray observations of IceCube-240419A
  13. GRB 240414A: AMI-LA radio observations
  14. GRB 240414A: LBT optical detection
  15. GRB 240419B : MITSuME Akeno optical upper limits
  16. Fermi GRB 240422A: Global MASTER-Net observations report
  17. GRB 240421B: AstroSat CZTI detection
  18. Fermi GRB 240421B: Global MASTER-Net observations report
  19. Swift GRB 240421B: Global MASTER-Net observations report
  20. GRB 240421B: Fermi GBM Observation
  21. GRB 240421B: J-band upper limits from WINTER
  22. GRB 240421B: Swift/UVOT Upper Limits
  23. Fermi GRB 240421A: Global MASTER-Net observations report
  24. EP240417a: no counterpart detection by SOAR
  25. EP240420a: TNT upper limit to its optical counterpart
  26. EP240420a: Nanshan optical counterpart observations
  27. EP240420a: GWAC-F50A optical upper limit
  28. LIGO/Virgo/KAGRA S240421ar: Identification of a GW unmodeled transient candidate
  29. EP240420a: detection of fading X-ray emission with refined position by EP-FXT
  30. EP240420a: NOT optical counterpart candidate and potential host
  31. GRB240419A: Skynet Optical Afterglow Analysis
  32. GRB240418A - Candidate afterglow from NIRES
  33. GRB 240419B: Swift/UVOT Upper Limits
  34. GRB 240419A: Swift/UVOT Upper Limits
  35. GRB 240419B: optical afterglow from the NOT
  36. EP240414a: Near-IR observations with NIRES and WINTER
  37. Swift GRB 240419B: Global MASTER-Net observations report
  38. EP240414A: Terskol Zeiss-2000 optical upper limit
  39. Swift GRB 240419A: Global MASTER-Net observations report
  40. GRB 240418A: Swift/UVOT Upper Limits
  41. GRB 240419A: REM NIR afterglow detection
  42. GRB 240411B: Swift/UVOT Detection
  43. EP240417a: YAHPT Optical Upper Limits
  44. GRB240418A: YAHPT Upper Limits
  45. GRB 240419A: VLT/UVES redshift of z = 5.178
  46. GRB 240419A: VLT optical afterglow detection
  47. EP240416a: J-band observations with WINTER
  48. EP240414a: GMG observation
  49. GRB 240418A: TSHAO Zeiss-1000 optical upper limit
  50. GRB 240418A: NOT optical upper limits
  51. GRB 240418A: AKO Upper Limit
  52. GRB 240411A: GOTO early optical upper limits
  53. Fermi GRB 240417A: Global MASTER-Net observations report
  54. LIGO/Virgo/KAGRA S240413p: X-ray upper limits from EP-WXT for the candidate AGN counterpart
  55. EP240416A: Terskol Zeiss-2000 optical upper limit
  56. EP240416A: Khureltogoot optical upper limit
  57. Improved IPN triangulation of GRB 240411A
  58. EP240416a: BOOTES-2/TELMA Optical Upper Limit
  59. EP240414a: GSP detects optical candidate counterpart AT2024gsa
  60. LIGO/Virgo/KAGRA S240413p: DECam GW-MMADS candidates
  61. EP240414a: Pan-STARRS detects re-brightening of the candidate counterpart AT2024gsa
  62. LIGO/Virgo/KAGRA S240413p: historical ATLAS and ZTF observations of the candidate AGN counterpart
  63. GRB 240415A: Glowbug gamma-ray detection
  64. GRB 240414A: Glowbug gamma-ray detection
  65. LIGO/Virgo/KAGRA S240413p: STEP - T80S Search and Candidate Counterpart Identification
  66. GRB 240415B: GECAM-B detection
  67. EP 240416a: Xinglong and NOT decaying optical counterpart
  68. GRB 240415A: Swift-BAT refined analysis
  69. EP240416A: MASTER optical observations
  70. GRB 240411A: Glowbug gamma-ray detection
  71. GRB 240414A: Swift-BAT refined analysis
  72. EP240416a: Kinder optical counterpart candidate
  73. GRB 240414A: AbAO optical upprer limit
  74. GRB 240415A: Swift/UVOT Detection
  75. EP240413a: BOOTES-2/TELMA Optical Upper Limit
  76. GRB 240415A: Fermi GBM Observation
  77. GRB 240414A: GAD Observatory, La Spezia, Italy ,upper limit
  78. GRB 240415A: Earliest optical followup with the Kinder observations
  79. GRB 240414A: GMG observation
  80. EP240414a: EP-FXT follow-up observation
  81. GRB 240415B: Swift ToO observations
  82. GRB 240415A: OHP/T193 optical observations
  83. GRB 240415A: optical afterglow detection from the INAF Asiago Observatory
  84. GRB 240415A: SAO RAS optical observations
  85. GRB 240415A: Mondy optical transient detection (photometry correction in GCN 36118 )
  86. GRB 240414A: Fermi GBM Observation
  87. Fermi GRB 240415A: Global MASTER-Net observations report
  88. GRB 240415A: Mondy optical transient detection
  89. GRB 240414A: Photometric observation from 2.2m CAHA
  90. IceCube-240412A: Upper limits from a search for additional neutrino events in IceCube
  91. GRB 240414A: Swift/UVOT Detection
  92. LXT 240402A/GRB 240402B: Swift follow-up observations
  93. GRB 240414A: Mondy optical observations
  94. GRB 240414A: AKO Optical Upper Limit
  95. X-ray transient EP 240414a - GTC spectroscopic observations
  96. GRB 240415A: Prompt Swift-XRT observations
  97. GRB 240415A: Swift detection of a burst
  98. EP240413a: Upper limits from GECAM-B Observation
  99. EP 240414a: NOT optical counterpart confirmation
  100. GRB240414A : J-band upper limits from WINTER

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