{"id":"https://openalex.org/W7220717373","doi":"https://doi.org/10.48550/arxiv.2610.04341","title":"The fading superorbital clock of Hercules X-1 in its 2025--2026 extended low state","display_name":"The fading superorbital clock of Hercules X-1 in its 2025--2026 extended low state","publication_year":2026,"publication_date":"2026-10-03","ids":{"openalex":"https://openalex.org/W7220717373","doi":"https://doi.org/10.48550/arxiv.2610.04341"},"language":"en","primary_location":{"id":"pmh:oai:arXiv.org:2610.04341","doi":null,"is_oa":true,"landing_page_url":"https://arxiv.org/abs/2610.04341","pdf_url":"https://arxiv.org/pdf/2610.04341","source":{"id":"https://openalex.org/S4306400194","display_name":"arXiv (Cornell University)","issn_l":"2331-8422","issn":["2331-8422"],"is_oa":true,"is_in_doaj":false,"is_core":false,"listed_in":[],"host_organization":"https://openalex.org/I205783295","host_organization_name":"Cornell University","host_organization_lineage":["https://openalex.org/I205783295"],"host_organization_lineage_names":[],"type":"repository"},"license":null,"license_id":null,"version":"submittedVersion","is_accepted":false,"is_published":false,"raw_source_name":null,"raw_type":"text"},"volume":null,"type":"preprint","is_traditional":true,"indexed_in":["arxiv","datacite"],"open_access":{"is_oa":true,"oa_status":"green","oa_url":"https://arxiv.org/pdf/2610.04341","any_repository_has_fulltext":true},"authorships":[{"author_position":"first","author":{"id":"https://openalex.org/A5004070608","display_name":"Zhenxuan Liao","orcid":"https://orcid.org/0000-0003-2221-0490","observed_orcids":["https://orcid.org/0000-0003-2221-0490"]},"institutions":[{"id":"https://openalex.org/I4210149962","display_name":"Sanming University","ror":"https://ror.org/044pany34","country_code":"CN","type":"education","lineage":["https://openalex.org/I4210149962"]}],"countries":["CN"],"is_corresponding":false,"raw_author_name":"Liao, Zhenxuan","raw_affiliation_strings":["School of Information Engineering , Sanming University , Jingdong Road 25 , Sanming 365004 , Fujian Province , People's Republic of China"],"raw_orcid":null,"affiliations":[{"raw_affiliation_string":"School of Information Engineering , Sanming University , Jingdong Road 25 , Sanming 365004 , Fujian Province , People's Republic of China","institution_ids":["https://openalex.org/I4210149962"]}]},{"author_position":"middle","author":{"id":"https://openalex.org/A5157705436","display_name":"Xinrui Tie","orcid":null,"observed_orcids":[]},"institutions":[{"id":"https://openalex.org/I4210149962","display_name":"Sanming University","ror":"https://ror.org/044pany34","country_code":"CN","type":"education","lineage":["https://openalex.org/I4210149962"]}],"countries":["CN"],"is_corresponding":false,"raw_author_name":"Tie, Xinrui","raw_affiliation_strings":["School of Information Engineering , Sanming University , Jingdong Road 25 , Sanming 365004 , Fujian Province , People's Republic of China"],"raw_orcid":null,"affiliations":[{"raw_affiliation_string":"School of Information Engineering , Sanming University , Jingdong Road 25 , Sanming 365004 , Fujian Province , People's Republic of China","institution_ids":["https://openalex.org/I4210149962"]}]},{"author_position":"middle","author":{"id":"https://openalex.org/A5157779675","display_name":"Yufeng Chi","orcid":"https://orcid.org/0009-0003-5892-8573","observed_orcids":["https://orcid.org/0009-0003-5892-8573"]},"institutions":[],"countries":[],"is_corresponding":false,"raw_author_name":"Chi, Yufeng","raw_affiliation_strings":[],"raw_orcid":null,"affiliations":[]},{"author_position":"last","author":{"id":"https://openalex.org/A5157691114","display_name":"Guanjun Lin","orcid":null,"observed_orcids":[]},"institutions":[{"id":"https://openalex.org/I4210149962","display_name":"Sanming University","ror":"https://ror.org/044pany34","country_code":"CN","type":"education","lineage":["https://openalex.org/I4210149962"]}],"countries":["CN"],"is_corresponding":false,"raw_author_name":"Lin, Guanjun","raw_affiliation_strings":["School of Information Engineering , Sanming University , Jingdong Road 25 , Sanming 365004 , Fujian Province , People's Republic of China"],"raw_orcid":null,"affiliations":[{"raw_affiliation_string":"School of Information Engineering , Sanming University , Jingdong Road 25 , Sanming 365004 , Fujian Province , People's Republic of China","institution_ids":["https://openalex.org/I4210149962"]}]}],"institutions":[],"countries_distinct_count":1,"institutions_distinct_count":1,"corresponding_author_ids":[],"corresponding_institution_ids":[],"apc_list":null,"apc_paid":null,"fwci":null,"has_fulltext":true,"cited_by_count":0,"citation_normalized_percentile":null,"cited_by_percentile_year":null,"biblio":{"volume":null,"issue":null,"first_page":null,"last_page":null},"is_retracted":false,"is_paratext":false,"is_xpac":false,"primary_topic":{"id":"https://openalex.org/T10744","display_name":"Astrophysical Phenomena and Observations","score":0.9976000189781189,"subfield":{"id":"https://openalex.org/subfields/3103","display_name":"Astronomy and Astrophysics"},"field":{"id":"https://openalex.org/fields/31","display_name":"Physics and Astronomy"},"domain":{"id":"https://openalex.org/domains/3","display_name":"Physical Sciences"}},"topics":[{"id":"https://openalex.org/T10744","display_name":"Astrophysical Phenomena and Observations","score":0.9976000189781189,"subfield":{"id":"https://openalex.org/subfields/3103","display_name":"Astronomy and Astrophysics"},"field":{"id":"https://openalex.org/fields/31","display_name":"Physics and Astronomy"},"domain":{"id":"https://openalex.org/domains/3","display_name":"Physical Sciences"}},{"id":"https://openalex.org/T10463","display_name":"Pulsars and Gravitational Waves Research","score":0.0017000000225380063,"subfield":{"id":"https://openalex.org/subfields/3103","display_name":"Astronomy and Astrophysics"},"field":{"id":"https://openalex.org/fields/31","display_name":"Physics and Astronomy"},"domain":{"id":"https://openalex.org/domains/3","display_name":"Physical Sciences"}},{"id":"https://openalex.org/T10818","display_name":"Astrophysics and Cosmic Phenomena","score":9.999999747378752e-05,"subfield":{"id":"https://openalex.org/subfields/3106","display_name":"Nuclear and High Energy Physics"},"field":{"id":"https://openalex.org/fields/31","display_name":"Physics and Astronomy"},"domain":{"id":"https://openalex.org/domains/3","display_name":"Physical Sciences"}}],"keywords":[{"id":"https://openalex.org/keywords/hercules-x-1","display_name":"Hercules X-1","score":1.0},{"id":"https://openalex.org/keywords/accreting-pulsars","display_name":"accreting pulsars","score":0.8080000281333923},{"id":"https://openalex.org/keywords/spin-down-torque","display_name":"spin-down torque","score":0.4819999933242798},{"id":"https://openalex.org/keywords/neutron-star-spin-evolution","display_name":"neutron star spin evolution","score":0.5329999923706055},{"id":"https://openalex.org/keywords/x-ray-pulsar-timing","display_name":"X-ray pulsar timing","score":0.5080000162124634}],"concepts":[{"id":"https://openalex.org/C121332964","wikidata":"https://www.wikidata.org/wiki/Q413","display_name":"Physics","level":0,"score":0.802299976348877},{"id":"https://openalex.org/C44870925","wikidata":"https://www.wikidata.org/wiki/Q37547","display_name":"Astrophysics","level":1,"score":0.7042999863624573},{"id":"https://openalex.org/C110363677","wikidata":"https://www.wikidata.org/wiki/Q4360","display_name":"Pulsar","level":2,"score":0.6747999787330627},{"id":"https://openalex.org/C81502235","wikidata":"https://www.wikidata.org/wiki/Q104225","display_name":"Precession","level":2,"score":0.6565999984741211},{"id":"https://openalex.org/C192887742","wikidata":"https://www.wikidata.org/wiki/Q4202","display_name":"Neutron star","level":2,"score":0.6323999762535095},{"id":"https://openalex.org/C1276947","wikidata":"https://www.wikidata.org/wiki/Q333","display_name":"Astronomy","level":1,"score":0.5742999911308289},{"id":"https://openalex.org/C90639681","wikidata":"https://www.wikidata.org/wiki/Q1940232","display_name":"Millisecond pulsar","level":3,"score":0.5094000101089478},{"id":"https://openalex.org/C68709404","wikidata":"https://www.wikidata.org/wiki/Q1134475","display_name":"Flux (metallurgy)","level":2,"score":0.47909998893737793},{"id":"https://openalex.org/C2776401274","wikidata":"https://www.wikidata.org/wiki/Q3756855","display_name":"Accretion (finance)","level":2,"score":0.4410000145435333},{"id":"https://openalex.org/C2781181686","wikidata":"https://www.wikidata.org/wiki/Q4226068","display_name":"Coherence (philosophical gambling strategy)","level":2,"score":0.40299999713897705},{"id":"https://openalex.org/C48103436","wikidata":"https://www.wikidata.org/wiki/Q599031","display_name":"State (computer science)","level":2,"score":0.36309999227523804},{"id":"https://openalex.org/C144171764","wikidata":"https://www.wikidata.org/wiki/Q48103","display_name":"Torque","level":2,"score":0.36039999127388},{"id":"https://openalex.org/C195803813","wikidata":"https://www.wikidata.org/wiki/Q237604","display_name":"Accretion disc","level":2,"score":0.33869999647140503},{"id":"https://openalex.org/C93682380","wikidata":"https://www.wikidata.org/wiki/Q2025226","display_name":"Static timing analysis","level":2,"score":0.31279999017715454},{"id":"https://openalex.org/C42704618","wikidata":"https://www.wikidata.org/wiki/Q910917","display_name":"Spin (aerodynamics)","level":2,"score":0.30880001187324524},{"id":"https://openalex.org/C123079801","wikidata":"https://www.wikidata.org/wiki/Q750240","display_name":"Modulation (music)","level":2,"score":0.30869999527931213},{"id":"https://openalex.org/C119698587","wikidata":"https://www.wikidata.org/wiki/Q2979836","display_name":"X-ray pulsar","level":3,"score":0.29100000858306885},{"id":"https://openalex.org/C17685861","wikidata":"https://www.wikidata.org/wiki/Q6960532","display_name":"Time derivative","level":2,"score":0.27889999747276306},{"id":"https://openalex.org/C130726490","wikidata":"https://www.wikidata.org/wiki/Q675076","display_name":"Light curve","level":2,"score":0.2685999870300293},{"id":"https://openalex.org/C44280652","wikidata":"https://www.wikidata.org/wiki/Q104837","display_name":"Phase (matter)","level":2,"score":0.2669999897480011},{"id":"https://openalex.org/C2779662365","wikidata":"https://www.wikidata.org/wiki/Q5416694","display_name":"Event (particle physics)","level":2,"score":0.25220000743865967},{"id":"https://openalex.org/C47091857","wikidata":"https://www.wikidata.org/wiki/Q4118612","display_name":"Coherence time","level":3,"score":0.25209999084472656}],"mesh":[],"locations_count":2,"locations":[{"id":"pmh:oai:arXiv.org:2610.04341","doi":null,"is_oa":true,"landing_page_url":"https://arxiv.org/abs/2610.04341","pdf_url":"https://arxiv.org/pdf/2610.04341","source":{"id":"https://openalex.org/S4306400194","display_name":"arXiv (Cornell University)","issn_l":"2331-8422","issn":["2331-8422"],"is_oa":true,"is_in_doaj":false,"is_core":false,"listed_in":[],"host_organization":"https://openalex.org/I205783295","host_organization_name":"Cornell University","host_organization_lineage":["https://openalex.org/I205783295"],"host_organization_lineage_names":[],"type":"repository"},"license":null,"license_id":null,"version":"submittedVersion","is_accepted":false,"is_published":false,"raw_source_name":null,"raw_type":"text"},{"id":"doi:10.48550/arxiv.2610.04341","doi":"https://doi.org/10.48550/arxiv.2610.04341","is_oa":true,"landing_page_url":"https://doi.org/10.48550/arxiv.2610.04341","pdf_url":null,"source":{"id":"https://openalex.org/S4306400194","display_name":"arXiv (Cornell University)","issn_l":"2331-8422","issn":["2331-8422"],"is_oa":true,"is_in_doaj":false,"is_core":false,"listed_in":[],"host_organization":"https://openalex.org/I205783295","host_organization_name":"Cornell University","host_organization_lineage":["https://openalex.org/I205783295"],"host_organization_lineage_names":[],"type":"repository"},"license":"cc-by","license_id":"https://openalex.org/licenses/cc-by","version":null,"is_accepted":false,"is_published":false,"raw_source_name":null,"raw_type":"Preprint"}],"best_oa_location":{"id":"pmh:oai:arXiv.org:2610.04341","doi":null,"is_oa":true,"landing_page_url":"https://arxiv.org/abs/2610.04341","pdf_url":"https://arxiv.org/pdf/2610.04341","source":{"id":"https://openalex.org/S4306400194","display_name":"arXiv (Cornell University)","issn_l":"2331-8422","issn":["2331-8422"],"is_oa":true,"is_in_doaj":false,"is_core":false,"listed_in":[],"host_organization":"https://openalex.org/I205783295","host_organization_name":"Cornell University","host_organization_lineage":["https://openalex.org/I205783295"],"host_organization_lineage_names":[],"type":"repository"},"license":null,"license_id":null,"version":"submittedVersion","is_accepted":false,"is_published":false,"raw_source_name":null,"raw_type":"text"},"sustainable_development_goals":[],"study_designs":[],"awards":[{"id":"https://openalex.org/G6271958458","display_name":"\u57fa\u4e8e\u591a\u5143\u8bed\u4e49\u878d\u5408\u7684\u6e90\u4ee3\u7801\u6f0f\u6d1e\u591a\u7c92\u5ea6\u68c0\u6d4b\u4e0e\u53ef\u89e3\u91ca\u673a\u5236\u7814\u7a76","funder_award_id":"2026J0011109","funder_id":"https://openalex.org/F4320321878","funder_display_name":"Natural Science Foundation of Fujian Province"},{"id":"https://openalex.org/G8329048047","display_name":"\u57fa\u4e8e\u4e2d\u5b50\u661f\u81ea\u65cb\u53d8\u5316\u7684Be/X\u5c04\u7ebf\u53cc\u661f\u7684\u5438\u79ef\u7269\u7406\u7814\u7a76","funder_award_id":"2024J01902","funder_id":"https://openalex.org/F4320321878","funder_display_name":"Natural Science Foundation of Fujian Province"},{"id":"https://openalex.org/G8417105889","display_name":null,"funder_award_id":"NSFC 12403051","funder_id":"https://openalex.org/F4320321001","funder_display_name":"National Natural Science Foundation of China"}],"funders":[{"id":"https://openalex.org/F4320321001","display_name":"National Natural Science Foundation of China","ror":"https://ror.org/01h0zpd94"},{"id":"https://openalex.org/F4320321878","display_name":"Natural Science Foundation of Fujian Province","ror":null},{"id":"https://openalex.org/F4320338247","display_name":"Moonshot Research and Development Program","ror":null}],"has_content":{"pdf":true,"grobid_xml":true},"content_urls":{"pdf":"https://content.openalex.org/works/W7220717373.pdf","grobid_xml":"https://content.openalex.org/works/W7220717373.grobid-xml"},"referenced_works_count":5,"referenced_works":["https://openalex.org/W4283314921","https://openalex.org/W4392311634","https://openalex.org/W7160501208","https://openalex.org/W7172413663","https://openalex.org/W7204437272"],"related_works":["https://openalex.org/W6981789639","https://openalex.org/W3126728900","https://openalex.org/W2106761835","https://openalex.org/W2327341400","https://openalex.org/W6903190463","https://openalex.org/W2165455556","https://openalex.org/W2978009654","https://openalex.org/W2963057623","https://openalex.org/W2039178628","https://openalex.org/W2310552618"],"abstract_inverted_index":{"We":[0,108],"present":[1],"two":[2],"decades":[3],"of":[4,7,45,76,84,95,143,150,221],"X-ray":[5,131],"monitoring":[6,230],"the":[8,21,43,60,70,74,77,85,110,128,136,139,144,148,162,170,178,185,194,200,205,209,213,222,228],"eclipsing":[9],"accreting":[10],"pulsar":[11,195],"Hercules":[12],"X-1":[13],"with":[14,127],"\\textit{Fermi}/GBM,":[15],"\\textit{Swift}/BAT":[16],"and":[17,38,120,135,169,212],"\\textit{MAXI}/GSC,":[18],"centred":[19],"on":[20],"extended":[22],"low":[23],"state":[24,80],"(ELS)":[25],"that":[26,184],"began":[27],"in":[28,35,59],"2025":[29],"May":[30],"(the":[31,81],"first":[32],"such":[33],"event":[34],"22":[36],"years)":[37],"is":[39,102,158,225],"still":[40],"ongoing":[41],"at":[42,165],"time":[44],"writing,":[46],"$\\sim$480~d":[47],"after":[48],"its":[49,96,191,203,216],"onset.":[50],"The":[51,64,99,122,153],"35-d":[52,86],"superorbital":[53,167],"clock":[54,72,201],"does":[55],"not":[56],"simply":[57],"stop":[58],"ELS;":[61],"it":[62],"fades.":[63],"surviving":[65],"modulation":[66],"stays":[67],"phase-locked":[68],"to":[69,90],"pre-ELS":[71,111],"until":[73],"flux":[75,132],"main":[78],"high":[79],"bright":[82],"phase":[83],"cycle)":[87],"has":[88],"decayed":[89],"a":[91],"few":[92],"per":[93],"cent":[94],"normal":[97],"level.":[98],"in-phase":[100],"coherence":[101],"then":[103],"lost,":[104],"around":[105],"2026":[106],"January--March.":[107],"classify":[109],"pulse-frequency":[112],"history":[113],"into":[114],"three":[115],"torque":[116,163,206],"states:":[117],"spin-up,":[118],"spin-down":[119,142],"flat.":[121],"spin":[123],"derivative":[124],"correlates":[125],"positively":[126],"main-high":[129],"hard":[130],"(Pearson":[133],"$r\\simeq0.7$),":[134],"ELS":[137],"hosts":[138],"longest":[140],"sustained":[141],"record,":[145],"$\\dot\u03bd\\approx-4.7\\times10^{-13}$~Hz~s$^{-1}$":[146],"over":[147,177],"$\\gtrsim$380~d":[149],"\\fer/GBM":[151],"coverage.":[152],"8--50":[154],"keV":[155],"pulse-profile":[156],"morphology":[157],"statistically":[159],"indistinguishable":[160],"across":[161],"states":[164],"fixed":[166],"phase,":[168,204],"shape":[171],"parameters":[172],"show":[173,183],"no":[174],"secular":[175],"drift":[176],"18-yr":[179],"record.":[180],"These":[181],"results":[182],"precessing":[186],"warped":[187],"accretion":[188,210],"disc":[189],"keeps":[190,202,207,215],"rhythm":[192],"while":[193],"fades":[196],"from":[197],"direct":[198],"view:":[199],"tracking":[208],"flux,":[211],"beam":[214],"shape.":[217],"No":[218],"free":[219],"precession":[220],"neutron":[223],"star":[224],"required":[226],"by":[227],"current":[229],"data.":[231]},"counts_by_year":[],"updated_date":"2026-11-08T12:12:28.789561","created_date":"2026-10-07T00:00:00"}
