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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"

16152 results found.

  1. EP240417a: no counterpart detection by SOAR
  2. EP240420a: TNT upper limit to its optical counterpart
  3. EP240420a: Xinglong decaying optical counterpart
  4. EP240420a: Nanshan optical counterpart observations
  5. EP240420a: GWAC-F50A optical upper limit
  6. EP240420a: NOT optical counterpart candidate and potential host
  7. GRB240419A: Skynet Optical Afterglow Analysis
  8. GRB240418A - Candidate afterglow from NIRES
  9. GRB 240419B: Swift/UVOT Upper Limits
  10. GRB 240419A: Swift/UVOT Upper Limits
  11. GRB 240419B: optical afterglow from the NOT
  12. EP240414a: Near-IR observations with NIRES and WINTER
  13. EP240414A: Terskol Zeiss-2000 optical upper limit
  14. GRB 240418A: Swift/UVOT Upper Limits
  15. GRB 240419A: REM NIR afterglow detection
  16. GRB 240411B: Swift/UVOT Detection
  17. EP240417a: YAHPT Optical Upper Limits
  18. GRB 240419A: VLT/UVES redshift of z = 5.178
  19. GRB 240419A: VLT optical afterglow detection
  20. EP240416a: J-band observations with WINTER
  21. EP240414a: GMG observation
  22. GRB 240418A: TSHAO Zeiss-1000 optical upper limit
  23. GRB 240418A: NOT optical upper limits
  24. GRB 240411A: GOTO early optical upper limits
  25. LIGO/Virgo/KAGRA S240413p: X-ray upper limits from EP-WXT for the candidate AGN counterpart
  26. EP240416A: Terskol Zeiss-2000 optical upper limit
  27. EP240416A: Khureltogoot optical upper limit
  28. EP240416a: BOOTES-2/TELMA Optical Upper Limit
  29. EP240414a: GSP detects optical candidate counterpart AT2024gsa
  30. EP240414a: Pan-STARRS detects re-brightening of the candidate counterpart AT2024gsa
  31. LIGO/Virgo/KAGRA S240413p: historical ATLAS and ZTF observations of the candidate AGN counterpart
  32. LIGO/Virgo/KAGRA S240413p: STEP - T80S Search and Candidate Counterpart Identification
  33. EP 240416a: Xinglong and NOT decaying optical counterpart
  34. EP240416A: MASTER optical observations
  35. EP240416a: Kinder optical counterpart candidate
  36. GRB 240414A: AbAO optical upprer limit
  37. GRB 240415A: Swift/UVOT Detection
  38. EP240413a: BOOTES-2/TELMA Optical Upper Limit
  39. GRB 240414A: GAD Observatory, La Spezia, Italy ,upper limit
  40. GRB 240415A: Earliest optical followup with the Kinder observations
  41. EP 240414a: BOOTES-4/MET Optical Upper Limits
  42. EP240414a: EP-FXT follow-up observation
  43. GRB 240415A: OHP/T193 optical observations
  44. GRB 240415A: optical afterglow detection from the INAF Asiago Observatory
  45. GRB 240415A: SAO RAS optical observations
  46. GRB 240415A: Mondy optical transient detection (photometry correction in GCN 36118 )
  47. GRB 240415A: Mondy optical transient detection
  48. GRB 240414A: Photometric observation from 2.2m CAHA
  49. GRB 240414A: Swift/UVOT Detection
  50. LXT 240402A/GRB 240402B: Swift follow-up observations
  51. GRB 240414A: Mondy optical observations
  52. GRB 240414A: AKO Optical Upper Limit
  53. EP 240414a: NOT optical counterpart confirmation
  54. GRB240414A : J-band upper limits from WINTER
  55. GRB 240414A : OHP/T193 second epoch of optical follow-up and afterglow detection
  56. GRB 240414A: MarSEC Observatory, Vicenza, Italy, UPPER LIMIT
  57. LIGO/Virgo/KAGRA S240413p: No Counterparts in DDOTI/OAN Optical Observations
  58. EP240413A: GOTO optical upper limits
  59. GRB 240414A: Skynet Optical Afterglow Observations
  60. EP240414a: Kinder optical counterpart candidate possibly associated with the galaxy SDSS J124601.99-094309.3
  61. GRB 240414A : MITSuME Akeno optical upper limits
  62. GRB 240414A : OHP/T193 redshift determination
  63. GRB 240414A : OHP/T193 optical counterpart detection
  64. EP240408a: GSP optical upper limit
  65. GRB 240411B: CrAO/ZTSh optical observations
  66. GRB 240411B: Kinder observations with Lulin observatory
  67. GRB 240411B: 1.3m DFOT Optical observations
  68. GRB 240411B: OHP/T193 optical observations
  69. GRB 240411B: LCO optical afterglow detection
  70. EP240408A: MASTER optical observations
  71. EP240408a: GROND detection of a candidate counterpart
  72. EP240408a: BOOTES-6/DPRT optical upper limit
  73. X-ray transient EP240315a: second epoch e-MERLIN radio observations
  74. IceCube-240327B: GRANDMA/Kilonova-Catcher observations of 4FGL J0555.9+0030 and optical upper limits
  75. X-ray transient LXT 240402A: WFST optical upper limits​
  76. GRB/FXT 240402B: Kinder optical counterpart candidate
  77. IceCube-240327B: GRANDMA observations of 4FGL J0555.9+0030
  78. GRB/FXT 240402B: VLT/FORS2 optical afterglow candidate
  79. X-ray transient LXT240402A: AST3-3 optical upper limits
  80. LXT 240402A: MASTER optical observations with AGN in error-box
  81. GRB 240402B: GWAC-F50A optical upper limit
  82. X-ray transient EP240331a: Kinder optical upper limits
  83. X-ray transient EP240331A: GRANDMA-Kilonova catcher optical upper limit
  84. EP240331A: MASTER optical observations
  85. Transient EP240315a: J-band observations of AT2024eju with WIRC
  86. X-ray transient EP20240331a: MeerLICHT optical upper limits
  87. X-ray transient EP240315a: continued ATCA monitoring
  88. X-ray transient EP240315a: e-MERLIN radio observations
  89. X-ray transient EP240315a: Ondrejov D50 optical limit
  90. Transient EPW20240219aa: REM optical/NIR further observations
  91. X-ray transient EP240315a: ATCA detection of radio counterpart
  92. X-ray transient EP240315a: GTC/HiPERCAM photometry
  93. X-ray transient EP240315a: MeerKAT radio detection
  94. X-ray transient EP240315a: GTC/OSIRIS spectroscopic redshift confirmation
  95. X-ray transient EP240315a: PRIME near infrared detection
  96. X-ray transient EP240315a: 3.6 m TNG NIR detection
  97. X-ray transient EP240315a/AT2024eju: TShAO (Zeiss-1000) observatory optical upper limit
  98. X-ray transient EP240315a: EP-FXT detection of the X-ray afterglow
  99. X-ray transient EP240315a: Kitab observatory optical upper limitns
  100. X-ray transient EP240315a: Montarrenti Observatory optical upper limit

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