Observational Evidence for Large-Scale Gas Heating in a Galaxy Protocluster at z=2.30

We report a $z=2.30$ galaxy protocluster (COSTCO-I) in the COSMOS field, where the Lyman-$\alpha$ forest as seen in the CLAMATO IGM tomography survey does not show significant absorption. This departs from the transmission-density relationship (often dubbed the fluctuating Gunn-Peterson approximation; FGPA) usually expected to hold at this epoch, which would lead one to predict strong Ly$\alpha$ absorption at the overdensity. For comparison, we generate mock Lyman-$\alpha$ forest maps by applying FGPA to constrained simulations of the COSMOS density field, and create mocks that incorporate the effects of finite sightline sampling, pixel noise, and Wiener filtering. Averaged over $r=15\,h^{-1}\,\mathrm{Mpc}$ around the protocluster, the observed Lyman-$\alpha$ forest is consistently more transparent in the real data than in the mocks, indicating a rejection of the null hypothesis that the gas in COSTCO-I follows FGPA ($p=0.0026$, or $2.79 \sigma$ significance). It suggests that the large-scale gas associated with COSTCO-I is being heated above the expectations of FGPA, which might be due to either large-scale AGN jet feedback or early gravitational shock heating. COSTCO-I is the first known large-scale region of the IGM that is observed to be transitioning from the optically-thin photoionized regime at Cosmic Noon, to eventually coalesce into an intra-cluster medium (ICM) by $z=0$. Future observations of similar structures will shed light on the growth of the ICM and allow constraints on AGN feedback mechanisms.Comment: 12 pages, 5 figures (including one interactive figure at https://member.ipmu.jp/chenze.dong/materials/COSTCO-I/). Accepted by ApJ

The Dependence of Galaxy Properties on the Underlying 3D Matter Density Field at 2.0<z<2.5

We study the environmental effect of galaxy evolution as a function of the underlying 3D dark matter density for the first time at $z=2-2.5$, in which the underlying matter density is reconstructed from galaxy and Ly$\alpha$ forest spectroscopy through dynamical forward modeling techniques. Utilizing these maps, we investigate the dependence of the star formation activities and galaxy types (mergers, submillimeter galaxies, active galactic nuclei, and quiescent galaxies) on the matter overdensity $\Delta$ and stellar mass. For the first time, we are able to probe underdense regions ($\Delta <1$) in addition to overdensities. We find that star formation activity generally depend on the stellar mass, not the matter density, except for high-mass galaxies ($M_*\geq10^{10.5}$ M$_\odot$) which show a drop in star formation activities by a factor of more than $30$ if they reside in high density regions with $\Delta\geq4-6$. We also find: (1) an absence of mergers and submillimeter galaxies in higher-density regions but otherwise no trend across lower-density bins, (2) the increase of active galactic nuclei and quiescent galaxy prevalence as a function of matter density, and (3) the increase of all aforementioned categories with the stellar mass. These results indicate that mass is the main driver of galaxy evolution. Nonetheless, we also find evidence for environmental quenching, particularly for high-mass galaxies in high-density environments. Our novel approach directly using reconstructed dark matter density maps demonstrates the new capability of the environmental effect studies in galaxy evolution at higher redshift.Comment: 21 pages, 11 figures, submitted to ApJ, comments welcom

Risk-based analytical modelling of managerial processes in shipping business

Gemi işletmeciliği faaliyetleri uluslararası platformda, y&uuml;ksek rekabet koşulları altında ve her ge&ccedil;en g&uuml;n y&uuml;kselen &ouml;z-denetim olgusu gibi kısıtlar altında y&uuml;r&uuml;t&uuml;lmektedir. Bu t&uuml;r kısıtlar, gemi işletmeciliğinde profesyonel anlayışa ge&ccedil;işe ve yenilik&ccedil;i y&uuml;r&uuml;tme faaliyetlerine s&uuml;rekli gelişim hedefi ile y&ouml;nelimi tetikler. Son yıllarda, sertifikalandırma kuruluşları ve denizcilik danışmanlık grupları gemi işletmeciliği idarecilerine Entegre Y&ouml;netim Sistemini (EYS) ileri bir &ccedil;&ouml;z&uuml;m aracı olarak &ouml;nermektedir. Gemi işletmeciliğinde EYS uygulamalarının kapsamı uluslararası tanınmış standartların gemi g&uuml;venliği ve gemilerden kaynaklanan kirliliğin &ouml;nlenmesi ile ilgili zorunlu denizcilik kurallarıyla birleştirilmesi esası &uuml;zerinedir. Bu noktada, standart gereksinimlerinin uyumluluğu ve ilgili kuralların gemi işletmeciliği y&ouml;netim organizasyonuna entegrasyonu iki temel sorun olarak ortaya &ccedil;ıkmaktadır. Bu araştırma ile Bulanık Bilgi Aksiyomu (BBA), Hata Ağacı Analizi (HAA), Analitik Ağ S&uuml;reci (AAS) ve diğer başlıca &Ccedil;ok &Ouml;l&ccedil;&uuml;tl&uuml; Karar Verme (&Ccedil;&Ouml;KV) y&ouml;ntemlerini de i&ccedil;eren bir Risk B&uuml;t&uuml;nleşik Karar Destek Sistemi (RBKDS) geliştirildi. RBKDS, Veri Tabanlı Y&ouml;netim Sistemi (VTYS), Model Esaslı Y&ouml;netim Sistemi (MEYS), BBA esaslı Model Se&ccedil;im Aray&uuml;z&uuml; (BBA-MSA), Entegre S&uuml;re&ccedil; Y&ouml;netim Mod&uuml;l&uuml; (ESYM), İdari Karar Verme Mod&uuml;l&uuml; (IKVM) ve Risk Kontrol Ve Y&ouml;netim Mod&uuml;l&uuml; (RKYM) gibi unsurların b&uuml;t&uuml;nleştirilmesi ile oluşmuştur. Tamamlanan prototip uygulama ile RBKDS&rsquo;ın EYS&rsquo;nin s&uuml;re&ccedil; temelli entegrasyonu ve gemi işletmeciliğinde y&ouml;netimsel s&uuml;re&ccedil;lerin risk temelli analitik &ccedil;&ouml;z&uuml;m&uuml; konusunda gemi işletmeciliği idarecilerini destekleyen nitel &ccedil;ıktılar ortaya koyduğu g&ouml;r&uuml;lm&uuml;şt&uuml;r. S&uuml;re&ccedil; idaresi prosed&uuml;rlerinin yeniden tasarımına karar desteğinin yanı sıra, RBKDS, ayrıca farklı standartlar arası uyumsuzluk risklerini de g&ouml;z &ouml;n&uuml;nde bulundurarak y&ouml;netimsel s&uuml;re&ccedil;ler &uuml;zerine etkin karar vermeyi sağlamaktadır.&nbsp; &nbsp;Anahtar Kelimeler: Gemi işletmeciliği, karar destek sistemi, entegre y&ouml;netim sistemi.Relevance to legislation in shipping business cycle, the International Maritime Organization (IMO) principally governs the safety and environmental protection via Flag State Implementation (FSI) and regional Port State Control (PSC) authorities in accordance with the designated Memorandum Of Understandings (MOUs). Although the IMO has adopted various conventions, mainly concerning marine safety, security, pollution prevention, and other relevant issues, enforcement of the international commitments and standards in trading activities of ships necessitate the involvement of maritime stakeholders. The IMO declared that there are now enough regulations in place and the problem is one of implementation and enforcement. In accordance with the recent trends in international maritime legislation, the implementation process of regulatory regime has become a competitive factor for the market players to achieve the sustainable development target in maritime transportation industry. Industrial response to this trend recalls the self-regulation. It is appeared as relatively a new regime for shipping business initiatives in maritime transportation industry. Extensively, the self-regulation dominates the industry and it mainly enforces the maritime stakeholders involvement in enhancement of the safety/environmental aspects for shipping business. Beside safety and environmental contributions, the self-regulation spontaneously ensures legislative performance of the relevant organizations such as classification societies, insurers, cargo owners, shippers, shipbrokers, ship managers, terminal operators and, ship financiers in trading activities satisfactorily. Implementation of an Integrated Management System (IMS) is one of the most effective and concrete instruments of managing the self-regulation phenomenon in order to respond to increasing demands from maritime society. In principle, the concept of IMS practices in shipping business is based on combining internationally recognized voluntary standards with the mandatory maritime 8regulations that are mainly concern with ship safety and the prevention of pollution from ships. In the early design phase of an IMS, cooperative efforts of maritime consultancies and relevant shipping executives targets to enable maximum improvement in managerial processes while reducing the costs and excessive bureaucracy in implementation of redesigned procedures. As potential clients, the third party groups such as cargo owners and contracted charterers have closely monitored the performance effects of IMS integration into professional shipping companies. Therefore, the managerial efforts are extremely valuable for the purpose of benefit from IMS implementations, which increase the reputation of ship management companies and provide an enormous trading advantage in maritime transportation industry. This research develops a Risk Integrated Decision Support System (RIDSS) based on a multi-methodological background includes Fuzzy Axiomatic Design (FAD) and Fault Tree Analysis (FTA), as well as Analytic Network Process (ANP) and other principal MCDM methods. The initial focus of the RIDSS is to reveal quantitative outcomes in order to encourage relevant shipping executives towards process-based integration of an IMS also to enhance risk-based analytical modelling of managerial processes in shipping business. The RIDSS consists of various modules such as Database Management System (DBMS), Model Base Management System (MBMS), FAD-based Model Selection Interface (FAD-MSI), Integrated Process Management Module (IPMM), Executive Decision-Making Module (EDMM), and Risk Control And Management Module (RCMM) with a high level of integrity. To demonstrate the proposed RIDSS, the mostly encountered managerial processes in commercial, technical, and operational levels of shipping business are then addressed and modelled. Specifically, the prototype application of the RIDSS incorporates the following process:(i) shipboard personnel recruitment, (ii) familiarization and training, (iii) performance appraisals of marine suppliers, (iv) marine equipment/spare purchasing, (v) fleet maintenance planning, (vi) accident analysis and prevention, (vii) Ship docking operations management, (viii) performance measurement for emergency drills. Besides decision aid to redesigning of process execution procedures through IMS requirements, the RIDSS also enables an effective decision-making on managerial processes even considering the potential risks of regulatory incompliance.  Keywords: Shipping business, decision support system, integrated management system.

The FRB20190520B Sightline Intersects Foreground Galaxy Clusters

The repeating fast radio burst FRB20190520B is an anomaly of the FRB population thanks to its high dispersion measure (DM$=1205\,pc\,cm^{-3}$) despite its low redshift of $z_\mathrm{frb}=0.241$. This excess has been attributed to a host contribution of ${DM_{host}} \approx 900\,\mathrm{pc\,cm^{-3}}$, far larger than any other known FRB. In this paper, we describe spectroscopic observations of the FRB20190520B field obtained as part of the FLIMFLAM survey on the 2dF/AAOmega facility, which yielded 701 galaxies redshifts in a field of $\approx 3\,\mathrm{deg}^2$. Applying a friends-of-friends group finder reveals multiple galaxy groups and clusters, for which we then estimated halo masses by comparing their richness with forward-modeled mocks from numerical simulations. We discover two separate $M_\mathrm{halo} >10^{14}\,M_\odot$ galaxy clusters, at $z=0.1867$ and $z=0.2170$, respectively, that are directly intersected by the FRB sightline within their characteristic radius $r_{200}$. Subtracting off their estimated DM contributions as well that of the diffuse intergalactic medium, we estimate a host contribution of $DM_{host}=467^{+140}_{-230}\,\mathrm{pc\,cm^{-3}}$ or ${DM_{host}} = 339^{+122}_{-174}\,\mathrm{pc\,cm^{-3}}$ (observed frame) depending on whether we assume the halo gas extends to $r_{200}$ or $2\times r_{200}$. This significantly smaller $DM_{host}$ -- no longer the largest known value -- is now consistent with H$\alpha$ emission measure estimates of the host galaxy without having to invoke unusually high gas temperatures. We also re-estimate the turbulent fluctuation and geometric amplification factor of the scattering layer to be $FG \approx 3.9 - 7.5\,(\mathrm{pc^2\;km})^{-1/3}$. This result illustrates the importance of incorporating foreground data for FRB analyses, both for understanding the nature of FRBs and to realize their potential as a cosmological probe.Comment: 14 pages, 5 figures, 2 tables. Interactive figure (link in text). Submitted to ApJ