The Dichotomy of the Mass-radius Relation and the Number of Globular Clusters

Abdullah, Ahmed H.; Kroupa, Pavel

doi:10.1134/s1063773721030014

Cited by 2 publications

(1 citation statement)

References 21 publications

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“…This work is established on the data group gathered from the NASA/IPAC Extragalactic Database (NED) surveys [22][23][24] , which is supported by the National Aeronautics and Space Administration and operated by the California Institute of Technology, such as Hubble luminosity distance (dL) of the Cosmic Microwave Background "CMB", and the velocity-integrated intensity SCO (for the transition J=1-0) in the unit (Jy. km/s).…”

Section: Sample Collections and Databasesmentioning

confidence: 99%

Comparison of physical characteristics of mass and luminosity function of disk systems in barred and unbarred spiral galaxies

M.N.,

Rashed,

AL-Dahlaki

2024

Baghdad Sci.J

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إحدى أهم الطرق لتقصي توزيع المجرات عبر الزمن الكوني هي دالة اللمعان LF بدلالة كتلة القرص الباريوني ψS(Mb)، القدر . لقد درسنا تقديرًا لكثافة كتلة الباريون في عينة من المجرات الحلزونية القضيبية وغير القضيبية من الادبيات السابقة، والتي تتضمن فعليًا، لكل صنف من الاجرام السماوية ذات المحتوى الباريون المرئي، جزءًا لا يتجزأ من ناتج دالة الضيائية (LF) ونسبة الكتلة إلى الضوء. استخدمت تقنية الانحدار المتعدد لحزمة البرامج الإحصائية في دراستنا ونتائجنا، مثل برنامج تحليل قواعد البيانات والرسوم البيانية)برامج Statistics Win و(Origin Pro . وفقًا للتحليل الإحصائي، هناك علاقة إيجابية قوية وارتباط وثيق للغاية (α MB~1), ، وغالبًا ما تظهر المجرات الحلزونية القرصية القضيبية وغير القضيبية قدراً مطلقاً بحدود MB < -18 mag . "الركبة" لدالة الضيائية للمجرات الحلزونية تبين قطعًا كبيرًا عند كتلة باريونية تبلغ Mb > 1010 Mʘ للمجرات الحلزونية القضيبية وغير القضيبية. يوفر هذا دليلاً يدعم الفرضية القائلة بأن اللوالب الحلزونية لنظام القرص بدأت تتشكل داخل عتبة كتلة متزايدة. نظرًا لأن زيادة دالة الكتلة الأولية للنجم مع الانزياح نحو الأحمر تكون أسرع بكثير، فقد أشارت النتائج التي توصلنا إليها إلى أن دالة الكتلة الأولية المنتقلة ψS(Mb) للمجرات القضيبية وغير القضيبيةعند انزياح أحمر مرتفع z > 0.027 للمجرات االقضيبية وz > 0.02للمجرات غير القضيبية والذي يبدو أنه يتناقص مقارنة بالكون الحرج.

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Section: Sample Collections and Databasesmentioning

confidence: 99%

Comparison of physical characteristics of mass and luminosity function of disk systems in barred and unbarred spiral galaxies

M.N.,

Rashed,

AL-Dahlaki

2024

Baghdad Sci.J

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Over 200 globular clusters in the Milky Way and still none with super-Solar metallicity

Garro,

Minniti,

Fernández-Trincado

2024

A&A

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A large number of globular clusters in the Milky Way have been studied in recent years, especially in hidden regions such as those of the Galactic bulge. The main goal of this work is to understand what we can learn if we include these new objects into the Milky Way globular cluster (GC) system that we know today. We compiled a catalog of 37 recently discovered globular clusters. Most of them are located in the Galactic bulge, but we also included some of the GCs for comparison. We used a range of distributions for investigating the Galactic GC system based on the metallicity, luminosity function, and age. We considered three samples. We first treated the new GC sample separately from the known and well characterized GCs. Consequently, we merged these two samples, thereby upgrading the Milky Way GC system. Furthermore, we performed a comparison between our clusters sample and the field star population. We found a double-peaked distribution for the luminosity function, which shows an elongated faint end tail. Considering the "merged" sample, the luminosity function peaks at $M_ V up 1.3$ mag and at V up 0.48$ mag. The metallicity distributions also display a bimodality trend. In this case, we compare our new sample compilation with previously published ones, finding that the distributions are in good general agreement. We also constructed the metallicity distribution for the field star sample and, by comparing it with that of the GCs, we learned that a high percentage of field stars show Fe/H $>0$; whereas we did not detect any GCs in the same metallicity range. To understand this inconsistency, we constructed the age-metallicity diagram for both samples, noting that the old and metal-poor population (age $ Gyr and Fe/H -1.0$) is represented by Gcs, while the young and metal-rich population (age $<8$ Gyr and Fe/H $>-1.0$) corresponds to field stars. From the analysis of the GC luminosity function and metallicity distribution, we can conclude that many GCs, probably those that are very faint, have survived strong dynamical processes that are typical of the bulge regions. Moreover, we cannot exclude the possibility that some of them have been accreted during past merging events, especially the metal-poor component, whereas the metal-rich population may be related to the formation of the bulge and/or disk. Finally, the difference that we notice between the cluster and field star samples should be explored in the context of the evolutionary differences among these two stellar populations.

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The Dichotomy of the Mass-radius Relation and the Number of Globular Clusters

Cited by 2 publications

References 21 publications

Comparison of physical characteristics of mass and luminosity function of disk systems in barred and unbarred spiral galaxies

Comparison of physical characteristics of mass and luminosity function of disk systems in barred and unbarred spiral galaxies

Over 200 globular clusters in the Milky Way and still none with super-Solar metallicity

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