- ID:
- ivo://CDS.VizieR/J/A+A/601/A117
- Title:
- Spitzer search for 19 planets
- Short Name:
- J/A+A/601/A117
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Short-period super-Earths and Neptunes are now known to be very frequent around solar-type stars. Improving our understanding of these mysterious planets requires the detection of a significant sample of objects suitable for detailed characterization. Searching for the transits of the low-mass planets detected by Doppler surveys is a straightforward way to achieve this goal. Indeed, Doppler surveys target the most nearby main-sequence stars, they regularly detect close-in low-mass planets with significant transit probability, and their radial velocity data constrain strongly the ephemeris of possible transits. In this context, we initiated in 2010 an ambitious Spitzer multi-Cycle transit search project that targeted 25 low-mass planets detected by radial velocity, focusing mainly on the shortest-period planets detected by the HARPS spectrograph. We report here null results for 19 targets of the project. For 16 planets out of 19, a transiting configuration is strongly disfavored or firmly rejected by our data for most planetary compositions.We derive a posterior probability of 83% that none of the probed 19 planets transits (for a prior probability of 22%), which still leaves a significant probability of 17% that at least one of them does transit. Globally, our Spitzer project revealed or confirmed transits for three of its 25 targeted planets, and discarded or disfavored the transiting nature of 20 of them. Our light curves demonstrate for Warm Spitzer excellent photometric precisions: for 14 targets out of 19, we were able to reach standard deviations that were better than 50ppm per 30 min intervals. Combined with its Earth-trailing orbit, which makes it capable of pointing any star in the sky and to monitor it continuously for days, this work confirms Spitzer as an optimal instrument to detect sub-mmag-deep transits on the bright nearby stars targeted by Doppler surveys.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/508/117
- Title:
- Spitzer selected starbursts at z~2
- Short Name:
- J/A+A/508/117
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Wide-field Spitzer surveys allow identification of thousands of potentially high-z submillimeter galaxies (SMGs) through their bright 24um emission and their mid-IR colors. We want to determine the average properties of such z~2 Spitzer-selected SMGs by combining millimeter, radio, and infrared photometry for a representative IR-flux (lambda_rest_~8um) limited sample of SMG candidates. A complete sample of 33 sources believed to be starbursts (5.8um-peakers) was selected in the (0.5deg^2^) J1046+56 field with selection criteria F_24um>400uJy, the presence of a redshifted stellar emission peak at 5.8um, and r'_Vega_>23. The field, part of the SWIRE Lockman Hole field, benefits from very deep VLA/GMRT 20cm, 50cm, and 90cm radio data (all 33 sources are detected at 50cm), and deep 160um and 70um Spitzer data. The 33 sources, with photometric redshifts ~1.5-2.5, were observed at 1.2mm with IRAM-30m/MAMBO to an rms ~0.7-0.8mJy in most cases. Their millimeter, radio, 7-band Spitzer, and near-IR properties were jointly analyzed.
- ID:
- ivo://CDS.VizieR/J/A+A/517/A44
- Title:
- Spitzer sources in the Galactic bulge
- Short Name:
- J/A+A/517/A44
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a photometric catalogue of seven selected fields towards the Galactic bulge, observed with the IRAC and MIPS imaging instruments on-board the Spitzer Space Telescope with unprecedented sensitivity. The locations of the fields are defined in Figure 1 and Table 1 of the paper. In each of the fields, tens of thousands of point sources were detected. The catalogue is split up into seven tables, according to the different fields. Table 5 in the paper gives ten lines of the band-merged catalogue of the Bulge N1 field as an example. In the first paper based on this data set, we present the observations, data reduction, the final catalogue of sources, and a detailed comparison to previous mid-IR surveys of the Galactic bulge, as well as to theoretical isochrones. We find in general good agreement with other surveys and the isochrones, supporting the high quality of our catalogue. Besides a catalogue for each field, fits files of the IRAC and MIPS mosaics are presented, too. As a cautionary note for the users, we would like to add that the least reliable sources in our catalogue are those with detection in only one IRAC band and no MIPS detection, and with (i) either no 2MASS and DENIS counterpart (depending on the field, between 3.1% and 6.7% of the sources), or (ii) a DENIS and 2MASS counterpart at a distance between 1.6 and 3 arcseconds (depending on the field, between 0.4% and 1.0% of the sources).
- ID:
- ivo://CDS.VizieR/J/ApJ/697/1993
- Title:
- Spitzer study of AGB stars. III.
- Short Name:
- J/ApJ/697/1993
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the third and final part of a census of asymptotic giant branch (AGB) stars in Local Group dwarf irregular (dIrr) galaxies. Papers I (Jackson et al. 2007ApJ...656..818J) and II (Jackson et al. 2007ApJ...667..891J) presented the results for WLM and IC 1613. Included here are Phoenix, LGS 3, DDO 210, Leo A, Pegasus dIrr, and Sextans A. Spitzer photometry at 3.6, 4.5, 5.8, and 8um are presented, along with a more thorough treatment of background galaxy contamination than was presented in Papers I and II. We find that at least a small population of completely optically obscured AGB stars exists in each galaxy, regardless of the galaxy's metallicity, but that higher metallicity galaxies tend to harbor more stars with slight infrared excesses.
- ID:
- ivo://CDS.VizieR/J/ApJ/698/1989
- Title:
- Spitzer survey of NGC 2451
- Short Name:
- J/ApJ/698/1989
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a Spitzer IRAC and MIPS survey of NGC 2451A and B, two open clusters in the 50-80Myr age range. We complement these data with extensive ground-based photometry and spectroscopy to identify the cluster members in the Spitzer survey field. We find only two members with 8um excesses. The incidence of excesses at 24um is much higher, i.e., 11 of 31 solar-like stars and 1 of 7 early-type (A) stars. This work nearly completes the debris disk surveys with Spitzer of clusters in the 30-130Myr range. This range is of interest because it is when large planetesimal collisions may have still been relatively common (as indicated by the one that led to the formation of the Moon during this period of the evolution of the solar system). We review the full set of surveys and find that there are only three possible cases out of about 250 roughly solar-mass stars where very large excesses suggest that such collisions have occurred recently.
- ID:
- ivo://CDS.VizieR/J/AJ/144/192
- Title:
- Spitzer survey of Orion A and B. I. YSO catalog
- Short Name:
- J/AJ/144/192
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a survey of the Orion A and B molecular clouds undertaken with the IRAC and MIPS instruments on board Spitzer. In total, five distinct fields were mapped, covering 9deg^2^ in five mid-IR bands spanning 3-24{mu}m. The survey includes the Orion Nebula Cluster, the Lynds 1641, 1630, and 1622 dark clouds, and the NGC 2023, 2024, 2068, and 2071 nebulae. These data are merged with the Two Micron All Sky Survey point source catalog to generate a catalog of eight-band photometry. We identify 3479 dusty young stellar objects (YSOs) in the Orion molecular clouds by searching for point sources with mid-IR colors indicative of reprocessed light from dusty disks or infalling envelopes. The YSOs are subsequently classified on the basis of their mid-IR colors and their spatial distributions are presented. We classify 2991 of the YSOs as pre-main-sequence stars with disks and 488 as likely protostars. Most of the sources were observed with IRAC in two to three epochs over six months; we search for variability between the epochs by looking for correlated variability in the 3.6 and 4.5{mu}m bands. We find that 50% of the dusty YSOs show variability. The variations are typically small (~0.2mag) with the protostars showing a higher incidence of variability and larger variations. The observed correlations between the 3.6, 4.5, 5.8, and 8{mu}m variability suggests that we are observing variations in the heating of the inner disk due to changes in the accretion luminosity or rotating accretion hot spots.
- ID:
- ivo://CDS.VizieR/J/ApJS/237/39
- Title:
- Spitzer survey of UltraVISTA deep Stripes (SMUVS)
- Short Name:
- J/ApJS/237/39
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper describes new deep 3.6 and 4.5{mu}m imaging of three UltraVISTA near-infrared survey stripes within the COSMOS field. The observations were carried out with Spitzer's Infrared Array Camera (IRAC) for the Spitzer Matching Survey of the UltraVISTA Deep Stripes (SMUVS). In this work we present our data reduction techniques, and document the resulting mosaics, coverage maps, and catalogs in both IRAC passbands for the three easternmost UltraVISTA survey stripes, covering a combined area of about 0.66deg^2^, of which 0.45deg^2^ have at least 20hr of integration time. SMUVS reaches point-source sensitivities of about 25.0 AB mag (0.13{mu}Jy) at both 3.6 and 4.5{mu}m, with a significance of 4{sigma}, accounting for both survey sensitivity and source confusion. To this limit the SMUVS catalogs contain a total of ~350,000 sources, each of which is detected significantly in at least one IRAC band. Because of its uniform and high sensitivity, relatively large area coverage, and the wide array of ancillary data available in COSMOS, the SMUVS survey will be useful for a large number of cosmological investigations.
- ID:
- ivo://CDS.VizieR/J/ApJS/184/18
- Title:
- Spitzer survey of young stellar clusters
- Short Name:
- J/ApJS/184/18
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a uniform mid-infrared imaging and photometric survey of 36 young, nearby, star-forming clusters and groups using Spitzer IRAC and MIPS. We have confidently identified and classified 2548 young stellar objects (YSOs) using recently established mid-infrared color-based methods. We have devised and applied a new algorithm for the isolation of local surface density enhancements from point source distributions, enabling us to extract the overdense cores of the observed star-forming regions for further analysis. We have compiled several basic structural measurements of these cluster cores from the data, such as mean surface densities of sources, cluster core radii, and aspect ratios, in order to characterize the ranges for these quantities. We find that a typical cluster core is 0.39pc in radius, has 26 members with infrared excess in a ratio of Class II to Class I sources of 3.7, is embedded in a A_Ks_=0.8mag cloud clump, and has a surface density of 60pc^-2^. We examine the nearest neighbor distances among the YSOs in several ways, demonstrating similarity in the spacings between Class II and Class I sources but large member clusters appear more dense than smaller clusters. We demonstrate that near-uniform source spacings in cluster cores are common, suggesting that simple Jeans fragmentation of parsec-scale cloud clumps may be the dominant process governing star formation in nearby clusters and groups. Finally, we compare our results to other similar surveys in the literature and discuss potential biases in the data to guide further interpretation.
- ID:
- ivo://CDS.VizieR/J/AJ/160/38
- Title:
- Spitzer variability detections of 79 brown dwarfs
- Short Name:
- J/AJ/160/38
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present Spitzer Space Telescope variability monitoring observations of three low-gravity L dwarfs with previous detections of variability in the near-IR: 2MASSJ0045+16, 2MASSJ0501-00, and 2MASSJ1425-36. We detect significant periodic variability in two of our targets, 2MASS J0045+16 and 2MASS J0501-00. We do not detect variability in 2MASS J1425-36. Combining our new rotation periods with rotational velocities, we calculate inclination angles of 22{deg}{+/-}1{deg}, 60_-8_^+13^{deg}, and 52_-13_^+19^{deg} for 2MASSJ0045+16, 2MASSJ0501-00, and 2MASSJ1425-36, respectively. Our three new objects are consistent with the tentative relations between inclination, amplitude, and color anomaly previously reported. Objects with the highest variability amplitudes are inclined equator on, while the maximum observed amplitude decreases as the inclination angle decreases. We also find a correlation between the inclination angle and (J-K)_2MASS_ color anomaly for the sample of objects with measured inclinations. Compiling the entire sample of brown dwarfs with Spitzer variability detections, we find no enhancement in amplitude for young, early-L dwarfs compared to the field dwarf population. We find a possible enhancement in amplitude of low-gravity late-L dwarfs at 4.5{mu}m. We do not find a correlation between amplitude ratio and spectral type for field dwarfs or for the young population. Finally, we compile the rotation periods of a large sample of brown dwarfs with ages 1Myr-1Gyr and compare the rotation rates predicted by evolutionary models assuming angular momentum conservation. We find that the rotation rates of the current sample of brown dwarfs fall within the expected range set by evolutionary models and breakup limits.
- ID:
- ivo://CDS.VizieR/J/ApJS/235/36
- Title:
- SPLASH-SXDF multi-wavelength photometric catalog
- Short Name:
- J/ApJS/235/36
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a multi-wavelength catalog in the Subaru/XMM-Newton Deep Field (SXDF) as part of the Spitzer Large Area Survey with Hyper-Suprime-Cam (SPLASH). We include the newly acquired optical data from the Hyper-Suprime-Cam Subaru Strategic Program, accompanied by IRAC coverage from the SPLASH survey. All available optical and near-infrared data is homogenized and resampled on a common astrometric reference frame. Source detection is done using a multi-wavelength detection image including the u-band to recover the bluest objects. We measure multi-wavelength photometry and compute photometric redshifts as well as physical properties for ~1.17 million objects over ~4.2deg^2^, with ~800000 objects in the 2.4deg^2^ HSC-Ultra-Deep coverage. Using the available spectroscopic redshifts from various surveys over the range of 0<z<6, we verify the performance of the photometric redshifts and we find a normalized median absolute deviation of 0.023 and outlier fraction of 3.2%. The SPLASH-SXDF catalog is a valuable, publicly available resource, perfectly suited for studying galaxies in the early universe and tracing their evolution through cosmic time.
