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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"

32770 results found.

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

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