Common origin for Hercules-Aquila and Virgo Clouds in Gaia DR2

We use a sample of ~350 RR Lyrae stars with radial velocities and Gaia DR2 proper motions to study orbital properties of the Hercules-Aquila Cloud (HAC) and Virgo Over-density (VOD). We demonstrate that both structures are dominated by stars on highly eccentric orbits, with peri-centres around ~1 kpc and apo-centres between 15 and 25 kpc from the Galactic centre. Given that the stars in the HAC and the VOD occupy very similar regions in the space spanned by integrals of motion, we conclude that these diffuse debris clouds are part of the same accretion event. More precisely, these inner halo sub-structures likely represent two complementary not-fully-mixed portions of an ancient massive merger, also known as the "sausage" event.Comment: Submitted to MNRAS. Comments welcome

Preoperative assessment of patients with inflammatory processes in the maxillo-facial region: a minireview

The statistical data show the continuosly increasing number of patients with chronic diseases and this fact has a significant impact on the workload of all clinicians, including maxillofacial surgeons. On the other hand, inflammatory processes in the maxillofacial region are an important problem for maxillofacial surgeons due to the high number of patients who present with this diagnosis, but also because of the life-threatening complications that may occur. Besides the usual complications, a maxillofacial surgeon has to be aware of other comorbidities of the patients diagnosed with inflammatory processes, falling into the category of medically complex patients. The preoperative assessment main purpose is to identify those patients for whom the perioperative period may present an increased risk of morbidity and mortality, aside from the known complications already associated with inflammatory processes. This article aims to emphasize the importance of performing a complete and meticulous preoperative assessment of every single patient, even the apparently healthy ones, since the patient himself may be unaware of a comorbidity he might have. In order to facilitate this process, the use of standardized questionnaires for different groups of patients is encouraged for the prompt assessment of the patient’s condition. Another suggestion is the use of standardized protocols for emergency situations that may occur with these patients, including the use of tables with possible drug interactions between the medication used for the management of their chronic disease with the medication administered in the maxillofacial surgery unit

Odontogenic orbital diseases – management considerations

Summary. Odontogenic orbital abscess and cellulitis is rare but the well-documented complication of sinusitis and infections spread from dental apical lesion. We report two cases of orbital abscess with periorbital cellulitis, with positive recent dental history and spreading infection into the maxillary sinus. The patients have shown facial edema, ocular pain, exophthalmia. A surgical intervention to drain the abscesses and a revision of the dental lesion and maxillary sinus were required.Introducere. Afectarea conținutului orbital și țesuturilor paraorbitale este o afecțiune gravă, cu evoluție fulminantă, care ar putea induce o infecție cerebrală odontogenă cu prognostic vital nefavorabil. Astfel diagnosticarea precoce și managementul corect va fi influențat de fiecare specialist implicat în conduita cazului dificil. Maladia are, de obicei, un debut acut cu dureri oculare și cefalee, stare de rău, febră, vertijuri, uneori cu simptome gastrice (vomă, grețuri). Local va fi prezent edemul pronunțat cu hiperemie și indurație (care uneori este confundat cu un abces al pleoapei), exoflamie, dureri pronunțate oculare și cefalee, scăderea mobilității oculare, scăderea acuității vizuale în unele cazuri. Conform datelor de literatură, afecțiunea survine în cazuri rare prin ascensiunea infecției de la molarii maxilari [1, 2]. Sunt 3 forme de ascensiune – hematogenă, limfatică, extensie directă [1, 4]. Procesul odontogen cu exoftalmie este determinat de așezarea anatomică și de microflora implicată în proces [3]. Anamneză stomatologică (intervenții sau afecțiuni netratate dentare la nivel de maxilar superior) este importantă în conduita acestor pacienți. Prezentare de cazuri. Caz clinic 1: Pacienta de 35 de ani, acuză edem și hiperemiea pleoapelor, dureri oculare intense, cefalee, febră, stare de rău. Cu o lună în urmă a suferit o intervenție dentară cu extracția a doi dinți din maxilarul superior. Peste 5 zile – infectare, dureri, febră. Tratament chirurgical la stomatolog – revizia plăgii infectate, drenare. Tratament antibacterian. Peste 5- 7 zile simptomele se repetă. Internată în Clinică Chirurgie maxilo- facială – intervenție, drenare, tratament medicamentos. Stare cu ameliorare. La 7 - 8 zile - agravarea stării, simptomele se repetă. Consultată – DC – abces al pleoapei – internată în secția oftalmologie pentru tratament chirurgical. Examinată în comun cu medicul ORL, apoi internată în secția ORL IMPS SR Orhei, cu clinica floridă de afecțiune inflamatorie acută cu edem al pleoapelor, hiperemie, cefalee, stare de rău. Tomografia computerizată – hiperecogenitate în sinusurile paranazale, maxilare, sfenoidale, exoftalmie și hiperecogenitate retrobulbară. Coordonare cu secția ORL SCR, efectuat transferul – în aceeași zi – tratament chirurgical cu deschiderea sinusurilor paranazale – toate, revizie, drenare. Tratament medicamentos. Stare cu ameliorare. Caz clinic 2: Bărbat de 32 de ani, internat în secția oftalmologie SR Orhei cu abces palpebral. Efectuate incizii, aplicate drenuri. A doua zi – ameliorare. La a 3-a zi – simptomele de inflamare reapar – se face revizia plăgilor și radiografia sinusurilor. Date de sinusită maxilară. Tratament chirurgical – drenarea sinusului și sanare la stomatolog. Concluzii. Abcesul retrobulbar cu exoftalmie și celulită este o afecțiune gravă care necesită o atenție sporită pentru un diagnostic precoce și management corect al afecțiunii

Spectroscopic Follow-Up of the Hercules Aquila Cloud

We designed a follow-up program to find the spectroscopic properties of the Hercules-Aquila Cloud (HAC) and test scenarios for its formation. We measured the radial velocities (RVs) of 45 RR Lyrae in the southern portion of the HAC using the facilities at the MDM observatory, producing the first large sample of velocities in the HAC. We found a double-peaked distribution in RVs, skewed slightly to negative velocities. We compared both the morphology of HAC projected onto the plane of the sky and the distribution of velocities in this structure outlined by RR Lyrae and other tracer populations at different distances to N-body simulations. We found that the behaviour is characteristic of an old, well-mixed accretion event with small apo-galactic radius. We cannot yet rule out other formation mechanisms for the HAC. However, if our interpretation is correct, HAC represents just a small portion of a much larger debris structure spread throughout the inner Galaxy whose distinct kinematic structure should be apparent in RV studies along many lines of sight.Comment: accepted by MNRAS; 12 pages, 7 figure

The Ages of Galactic Bulge Stars with Realistic Uncertainties

Using modern isochrones with customized physics and carefully considered statistical techniques, we recompute the age distribution for a sample of 91 micro-lensed dwarfs in the Galactic bulge presented by Bensby et al. (2017) and do not produce an age distribution consistent with their results. In particular, our analysis finds that only 15 of 91 stars have ages younger than 7 Gyr, compared to their finding of 42 young stars in the same sample. While we do not find a constituency of very young stars, our results do suggest the presence of an $\sim8$ Gyr population at the highest metallicities, thus contributing to long-standing debate about the age--metallicity distribution of the Galactic bulge. We supplement this with attempts at independent age determinations from two sources of photometry, BDBS and \textit{Gaia}, but find that the imprecision of photometric measurements prevents reliable age and age uncertainty determinations. Lastly, we present age uncertainties derived using a first-order consideration of global modeling uncertainties in addition to standard observational uncertainties. The theoretical uncertainties are based on the known variance of free parameters in the 1D stellar evolution models used to generate isochrones, and when included, result in age uncertainties of $2$--$5$ Gyr for this spectroscopically well-constrained sample. These error bars, which are roughly twice as large as typical literature values, constitute realistic lower limits on the true age uncertainties.Comment: accepted to ApJ; revisions complet

Insights into the Galactic Bulge Chemodynamical Properties from Gaia Data Release 3

We explore the chemodynamical properties of the Galaxy in the azimuthal velocity V ϕ and metallicity [Fe/H] space using red giant stars from Gaia Data Release 3. The row-normalized V ϕ –[Fe/H] maps form a coherent sequence from the bulge to the outer disk, clearly revealing the thin/thick disk and the Splash. The metal-rich stars display bar-like kinematics, while the metal-poor stars show dispersion-dominated kinematics. The intermediate-metallicity population (−1 − 1 dex, with the Splash not participating in the bar formation and growth. Moreover, with a set of isolated evolving N-body disk simulations, we confirm that a nonrotating classical bulge can be spun up by the bar and develop cylindrical rotation, consistent with the observations for the metal-poor stars

Mapping the tilt of the Milky Way bulge velocity ellipsoids with ARGOS and Gaia DR2

Until the recent advent of $Gaia$ Data Release 2 (DR2) and deep multi-object spectroscopy, it has been difficult to obtain 6-D phase space information for large numbers of stars beyond 4 kpc, in particular towards the Galactic centre, where dust and crowding effects are significant. In this study we combine line-of-sight velocities from the Abundances and Radial velocity Galactic Origins Survey (ARGOS) spectroscopic survey with proper motions from $Gaia$ DR2, to obtain a sample of $\sim$ 7,000 red clump stars with 3-D velocities. We perform a large scale stellar kinematics study of the Milky Way (MW) bulge to characterize the bulge velocity ellipsoids. We measure the tilt $l_{v}$ of the major-axis of the velocity ellipsoid in the radial-longitudinal velocity plane in 20 fields across the bulge. The tilt or vertex deviation, is characteristic of non-axisymmetric systems and a significant tilt is a robust indicator of non-axisymmetry or bar presence. We compare the observations to the predicted kinematics of an N-body boxy-bulge model formed from dynamical instabilities. In the model, the $l_{v}$ values are strongly correlated with the angle ($\alpha$) between the bulge major-axis and the Sun-Galactic centre line-of-sight. We use a maximum likelihood method to obtain an independent measurement of $\alpha$, from bulge stellar kinematics alone. The most likely value of $\alpha$ given our model is $\alpha = (29 \pm 3)^{\circ}$. In the Baade's window, the metal-rich stars display a larger vertex deviation ($l_{v} = -40^{\circ}$) than the metal-poor stars ($l_{v} = 10^{\circ}$) but we do not detect significant $l_{v}-$metallicity trends in the other fields.Comment: 13 pages, 11 figure

The Blanco DECam Bulge Survey (BDBS) VIII: Chemo-kinematics in the southern Galactic bulge from 2.3 million red clump stars with Gaia DR3 proper motions

The Blanco DECam Bulge Survey (BDBS) provides near-ultraviolet to near-infrared photometry for ~250 million unique stars. By combining BDBS photometry with the latest Gaia astrometry, we characterize the chemo-dynamics of red clump stars across the BDBS footprint, using an unprecedented sample size and sky coverage. We construct a sample of ~2.3 million red clump giants in the bulge with photometric metallicities, BDBS photometric distances, and proper motions. We study the kinematics of the red clump stars as a function of sky position and metallicity, by investigating proper motion rotation curves, velocity dispersions, and proper motion correlations across the southern Galactic bulge. We find that metal-poor red clump stars exhibit lower rotation amplitudes, at ~29 km s$^{-1}$ kpc^{-1}. The peak of the angular velocity is ~39 km s^{-1} kpc^{-1} for [Fe/H] ~ -0.2 dex, exhibiting declining rotation at higher [Fe/H]. The velocity dispersion is higher for metal-poor stars, while metal-rich stars show a steeper gradient with Galactic latitude, with a maximum dispersion at low latitudes along the bulge minor axis. Only metal-rich stars ([Fe/H] >~ -0.5 dex) show clear signatures of the bar in their kinematics, while the metal-poor population exhibits isotropic motions with an axisymmetric pattern around Galactic longitude l = 0. This work reports the largest sample of bulge stars with distance, metallicity, and astrometry and shows clear kinematic differences with metallicity. The global kinematics over the bulge agrees with earlier studies. However, we see striking changes with increasing metallicity and for the first time, see kinematic differences for stars with [Fe/H]>-0.5, suggesting that the bar itself may have kinematics that depends on metallicity.Comment: 12 pages, Accepted for publication in A&